From 94e7b44ebc1710eed0f870428ddb5bfcd85858fa Mon Sep 17 00:00:00 2001
From: Michael Drake <tlsa@netsurf-browser.org>
Date: Mon, 14 Feb 2011 22:05:39 +0000
Subject: Pass clip rect to clip plotters as struct.  Simplify clip rect
 handling in debug window code.  Pass clip rect to select menu as struct.

svn path=/trunk/netsurf/; revision=11683
---
 amiga/plotters.c                | 13 ++++---
 amiga/plotters.h                |  2 +-
 atari/browser.c                 | 20 ++++++----
 atari/plot.c                    |  4 +-
 atari/plot.h                    |  4 +-
 beos/beos_plotters.cpp          | 37 ++++++++++++-------
 cocoa/plotter.m                 |  6 +--
 desktop/browser.c               |  2 +-
 desktop/history_core.c          |  7 +++-
 desktop/knockout.c              | 77 +++++++++++++--------------------------
 desktop/plotters.h              |  3 +-
 desktop/save_pdf/pdf_plotters.c | 15 ++++----
 desktop/textarea.c              |  4 +-
 desktop/tree.c                  | 29 ++++++++-------
 framebuffer/framebuffer.c       | 14 +++----
 gtk/plotters.c                  | 14 +++----
 gtk/print.c                     | 12 +++---
 gtk/scaffolding.c               | 10 +++--
 gtk/thumbnail.c                 |  2 +-
 render/form.c                   | 30 ++++++++-------
 render/form.h                   |  5 +--
 render/html_redraw.c            | 43 ++++++++++++----------
 riscos/debugwin.c               | 81 ++++++++++++++++++-----------------------
 riscos/gui/progress_bar.c       | 18 ++++-----
 riscos/plotters.c               | 14 +++----
 riscos/print.c                  |  6 +--
 riscos/save_draw.c              |  6 +--
 riscos/treeview.c               | 11 +++---
 windows/plot.c                  | 13 +++----
 29 files changed, 246 insertions(+), 256 deletions(-)

diff --git a/amiga/plotters.c b/amiga/plotters.c
index f89b12c04..9c61ad259 100755
--- a/amiga/plotters.c
+++ b/amiga/plotters.c
@@ -400,7 +400,7 @@ bool ami_polygon(const int *p, unsigned int n, const plot_style_t *style)
 }
 
 
-bool ami_clip(int x0, int y0, int x1, int y1)
+bool ami_clip(const struct rect *clip)
 {
 	#ifdef AMI_PLOTTER_DEBUG
 	LOG(("[ami_plotter] Entered ami_clip()"));
@@ -412,10 +412,10 @@ bool ami_clip(int x0, int y0, int x1, int y1)
 	{
 		reg = NewRegion();
 
-		glob->rect.MinX = x0;
-		glob->rect.MinY = y0;
-		glob->rect.MaxX = x1-1;
-		glob->rect.MaxY = y1-1;
+		glob->rect.MinX = clip->x0;
+		glob->rect.MinY = clip->y0;
+		glob->rect.MaxX = clip->x1-1;
+		glob->rect.MaxY = clip->y1-1;
 
 		OrRectRegion(reg,&glob->rect);
 
@@ -426,7 +426,8 @@ bool ami_clip(int x0, int y0, int x1, int y1)
 
 #ifdef NS_AMIGA_CAIRO_ALL
 	cairo_reset_clip(glob->cr);
-	cairo_rectangle(glob->cr, x0, y0, x1 - x0, y1 - y0);
+	cairo_rectangle(glob->cr, clip->x0, clip->y0,
+			clip->x1 - clip->x0, clip->y1 - clip->y0);
 	cairo_clip(glob->cr);
 #endif
 
diff --git a/amiga/plotters.h b/amiga/plotters.h
index c58acfb8e..7bd42af6f 100755
--- a/amiga/plotters.h
+++ b/amiga/plotters.h
@@ -46,7 +46,7 @@ bool ami_clg(colour c);
 bool ami_rectangle(int x0, int y0, int x1, int y1, const plot_style_t *style);
 bool ami_line(int x0, int y0, int x1, int y1, const plot_style_t *style);
 bool ami_polygon(const int *p, unsigned int n, const plot_style_t *style);
-bool ami_clip(int x0, int y0, int x1, int y1);
+bool ami_clip(const struct rect *clip);
 bool ami_text(int x, int y, const char *text, size_t length, 
 		const plot_font_style_t *fstyle);
 bool ami_disc(int x, int y, int radius, const plot_style_t *style);
diff --git a/atari/browser.c b/atari/browser.c
index 2c667a5d7..8d2f79ca5 100755
--- a/atari/browser.c
+++ b/atari/browser.c
@@ -873,9 +873,7 @@ static void browser_redraw_content( struct gui_window * gw, int xoff, int yoff )
 		clip.x1 = b->redraw.area.x1 + b->scroll.current.x;
 		clip.y1 = b->redraw.area.y1 + b->scroll.current.y;
 		/* must clear the surface: */
-		plot.clip(  b->redraw.area.x0, b->redraw.area.y0, 
-					b->redraw.area.x1, b->redraw.area.y1
-		);
+		plot.clip(&clip);
 		plot.rectangle( b->redraw.area.x0, 
 						b->redraw.area.y0, 
 						b->redraw.area.x1, 
@@ -911,16 +909,24 @@ void browser_redraw_caret( struct gui_window * gw, GRECT * area )
 		caret.g_x -= gw->browser->scroll.current.x;
 		caret.g_y -= gw->browser->scroll.current.y;
 		struct s_clipping oldclip;
+		struct rect old_clip;
+		struct rect clip;
+		clip.x0 = caret.g_x - 1;
+		clip.y0 = caret.g_y - 1;
+		clip.x1 = caret.g_x + caret.g_w + 1;
+		clip.y1 = caret.g_y + caret.g_h + 1;
 		plot_get_clip( &oldclip );
 		/* clip to cursor: */
-		plot_clip( caret.g_x-1, caret.g_y -1, 
-			caret.g_x + caret.g_w + 1, caret.g_y + caret.g_h + 1
-		);
+		plot_clip( &clip );
 		plot_rectangle( caret.g_x, caret.g_y, 
 			caret.g_x+caret.g_w, caret.g_y+caret.g_h,
 			plot_style_caret );
 		/* restore clip area: */
-		plot_clip( oldclip.x0, oldclip.y0, oldclip.x1,oldclip.y1);
+		old_clip.x0 = old_clip.x0;
+		old_clip.y0 = old_clip.y0;
+		old_clip.x1 = old_clip.x1;
+		old_clip.y1 = old_clip.y1;
+		plot_clip( &old_clip );
 		b->caret.current.g_x = caret.g_x + gw->browser->scroll.current.x;
 		b->caret.current.g_y = caret.g_y + gw->browser->scroll.current.y;
 		b->caret.current.g_w = caret.g_w;
diff --git a/atari/plot.c b/atari/plot.c
index 2bfe37923..2d45f1f63 100755
--- a/atari/plot.c
+++ b/atari/plot.c
@@ -110,9 +110,9 @@ static bool plot_polygon(const int *p, unsigned int n,
 	return ( true );
 }
 
-bool plot_clip(int x0, int y0, int x1, int y1)
+bool plot_clip(const struct rect *clip)
 {
-	plotter->clip( plotter, x0, y0, x1, y1 );
+	plotter->clip( plotter, clip->x0, clip->y0, clip->x1, clip->y1 );
 	return ( true );
 }
 
diff --git a/atari/plot.h b/atari/plot.h
index ed86041e5..a11b6d576 100755
--- a/atari/plot.h
+++ b/atari/plot.h
@@ -22,11 +22,13 @@
 #include "desktop/plotters.h"
 #include "atari/plot/plotter.h"
 
+struct rect;
+
 int atari_plotter_init( char*, char * );
 int atari_plotter_finalise( void );
 
 bool plot_get_clip(struct s_clipping * out);
-bool plot_clip(int x0, int y0, int x1, int y1);
+bool plot_clip(const struct rect *clip);
 bool plot_rectangle( int x0, int y0, int x1, int y1,const plot_style_t *style );
 
 #endif
diff --git a/beos/beos_plotters.cpp b/beos/beos_plotters.cpp
index e3372963e..8c65d7ac3 100644
--- a/beos/beos_plotters.cpp
+++ b/beos/beos_plotters.cpp
@@ -66,8 +66,7 @@ static bool nsbeos_plot_line(int x0, int y0, int x1, int y1, const plot_style_t
 static bool nsbeos_plot_polygon(const int *p, unsigned int n, const plot_style_t *style);
 static bool nsbeos_plot_path(const float *p, unsigned int n, colour fill, float width,
                     colour c, const float transform[6]);
-static bool nsbeos_plot_clip(int clip_x0, int clip_y0,
-		int clip_x1, int clip_y1);
+static bool nsbeos_plot_clip(const struct clip *rect);
 static bool nsbeos_plot_text(int x, int y, const char *text, size_t length, 
 		const plot_font_style_t *fstyle);
 static bool nsbeos_plot_disc(int x, int y, int radius, const plot_style_t *style);
@@ -316,8 +315,7 @@ bool nsbeos_plot_polygon(const int *p, unsigned int n, const plot_style_t *style
 
 
 
-bool nsbeos_plot_clip(int clip_x0, int clip_y0,
-		int clip_x1, int clip_y1)
+bool nsbeos_plot_clip(const struct rect *ns_clip)
 {
 	BView *view;
 	//fprintf(stderr, "%s(%d, %d, %d, %d)\n", __FUNCTION__, clip_x0, clip_y0, clip_x1, clip_y1);
@@ -328,7 +326,8 @@ bool nsbeos_plot_clip(int clip_x0, int clip_y0,
 		return false;
 	}
 
-	BRect rect(clip_x0, clip_y0, clip_x1 - 1, clip_y1 - 1);
+	BRect rect(ns_clip->x0, ns_clip->y0, ns_clip->x1 - 1,
+			ns_clip->y1 - 1);
 	BRegion clip(rect);
 	view->ConstrainClippingRegion(NULL);
 	if (view->Bounds() != rect)
@@ -341,15 +340,15 @@ bool nsbeos_plot_clip(int clip_x0, int clip_y0,
 #ifdef CAIRO_VERSION
   	if (option_render_cairo) {
 		cairo_reset_clip(current_cr);
-		cairo_rectangle(current_cr, clip_x0, clip_y0,
-			clip_x1 - clip_x0, clip_y1 - clip_y0);
+		cairo_rectangle(current_cr, clip->x0, clip->y0,
+			clip->x1 - clip->x0, clip->y1 - clip->y0);
 		cairo_clip(current_cr);
 	}
 #endif
-	cliprect.x = clip_x0;
-	cliprect.y = clip_y0;
-	cliprect.width = clip_x1 - clip_x0;
-	cliprect.height = clip_y1 - clip_y0;
+	cliprect.x = clip->x0;
+	cliprect.y = clip->y0;
+	cliprect.width = clip->x1 - clip->x0;
+	cliprect.height = clip->y1 - clip->y0;
 	gdk_gc_set_clip_rectangle(current_gc, &cliprect);
 #endif
 	return true;
@@ -835,6 +834,7 @@ static void test_plotters(void)
 {
 	int x0, y0;
 	int x1, y1;
+	struct rect r;
 
 	x0 = 5;
 	y0 = 5;
@@ -853,10 +853,21 @@ static void test_plotters(void)
 	plot.fill(x0, y0, x1, y1, 0x00ff0000);
 	plot.rectangle(x0+10, y0+10, x1-x0+1, y1-y0+1, 2, 0x00ffff00, true, false);
 	y0+=30; y1+=30;
-	plot.clip(x0 + 2, y0 + 2, x1 - 2, y1 - 2);
+
+	r.x0 = x0 + 2;
+	r.y0 = y0 + 2;
+	r.x1 = x1 - 2;
+	r.y1 = y1 - 2;
+	plot.clip(&r);
+
 	plot.fill(x0, y0, x1, y1, 0x00000000);
 	plot.disc(x1, y1, 8, 0x000000ff, false);
-	plot.clip(0, 0, 300, 300);
+
+	r.x0 = 0;
+	r.y0 = 0;
+	r.x1 = 300;
+	r.y1 = 300;
+	plot.clip(&r);
 
 	y0+=30; y1+=30;
 	
diff --git a/cocoa/plotter.m b/cocoa/plotter.m
index 63ec807a0..c51e82c91 100644
--- a/cocoa/plotter.m
+++ b/cocoa/plotter.m
@@ -124,9 +124,9 @@ void cocoa_set_clip( NSRect rect )
 	cocoa_plot_clip_rect = rect;
 }
 
-static bool plot_clip(int x0, int y0, int x1, int y1)
+static bool plot_clip(const struct rect *clip)
 {
-	cocoa_plot_clip_rect = cocoa_rect( x0, y0, x1, y1 );
+	cocoa_plot_clip_rect = cocoa_rect( clip->x0, clip->y0, clip->x1, clip->y1 );
 	return true;
 }
 
@@ -329,4 +329,4 @@ static inline void cocoa_center_pixel( bool x, bool y )
 	NSAffineTransform *transform = [NSAffineTransform transform];
 	[transform translateXBy: x ? cocoa_half_pixel : 0.0 yBy: y ? cocoa_half_pixel : 0.0];
 	[transform concat];
-}
\ No newline at end of file
+}
diff --git a/desktop/browser.c b/desktop/browser.c
index 36661f1de..351b327c6 100644
--- a/desktop/browser.c
+++ b/desktop/browser.c
@@ -100,7 +100,7 @@ bool browser_window_redraw(struct browser_window *bw, int x, int y,
 		return false;
 	}
 
-	plot.clip(clip->x0, clip->y0, clip->x1, clip->y1);
+	plot.clip(clip);
 
 	if (bw->current_content == NULL) {
 		return plot.rectangle(clip->x0, clip->y0, clip->x1, clip->y1,
diff --git a/desktop/history_core.c b/desktop/history_core.c
index ee964ad6d..96a760a9d 100644
--- a/desktop/history_core.c
+++ b/desktop/history_core.c
@@ -628,7 +628,12 @@ bool history_redraw_entry(struct history *history,
 	plot_font_style_t fstyle = *plot_style_font;
 
 	if (clip) {
-		if(!plot.clip(x0 + xoffset, y0 + yoffset, x1 + xoffset, y1 + yoffset))
+		struct rect rect;
+		rect.x0 = x0 + xoffset;
+		rect.y0 = y0 + yoffset;
+		rect.x1 = x1 + xoffset;
+		rect.y1 = y1 + yoffset;
+		if(!plot.clip(&rect))
 			return false;
 	}
 
diff --git a/desktop/knockout.c b/desktop/knockout.c
index 680257b0f..3525df972 100644
--- a/desktop/knockout.c
+++ b/desktop/knockout.c
@@ -88,8 +88,7 @@ static bool knockout_plot_bitmap_recursive(struct knockout_box *box,
 static bool knockout_plot_line(int x0, int y0, int x1, int y1, const plot_style_t *pstyle);
 static bool knockout_plot_polygon(const int *p, unsigned int n, const plot_style_t *pstyle);
 static bool knockout_plot_rectangle(int x0, int y0, int x1, int y1, const plot_style_t *plot_style);
-static bool knockout_plot_clip(int clip_x0, int clip_y0,
-		int clip_x1, int clip_y1);
+static bool knockout_plot_clip(const struct rect *clip);
 static bool knockout_plot_text(int x, int y, const char *text, size_t length, 
 		const plot_font_style_t *fstyle);
 static bool knockout_plot_disc(int x, int y, int radius, const plot_style_t *pstyle);
@@ -137,12 +136,7 @@ typedef enum {
 
 
 struct knockout_box {
-	struct {
-		int x0;
-		int y0;
-		int x1;
-		int y1;
-	} bbox;
+	struct rect bbox;
 	bool deleted;			/* box has been deleted, ignore */
 	struct knockout_box *child;
 	struct knockout_box *next;
@@ -179,12 +173,7 @@ struct knockout_entry {
 			int y1;
 			plot_style_t plot_style;
 		} fill;
-		struct {
-			int x0;
-			int y0;
-			int x1;
-			int y1;
-		} clip;
+		struct rect clip;
 		struct {
 			int x;
 			int y;
@@ -232,10 +221,7 @@ static struct knockout_box *knockout_list = NULL;
 
 static struct plotter_table real_plot;
 
-static int clip_x0_cur;
-static int clip_y0_cur;
-static int clip_x1_cur;
-static int clip_y1_cur;
+static struct rect clip_cur;
 static int nested_depth = 0;
 
 /**
@@ -339,10 +325,7 @@ bool knockout_plot_flush(void)
 			break;
 		case KNOCKOUT_PLOT_CLIP:
 			success &= plot.clip(
-					knockout_entries[i].data.clip.x0,
-					knockout_entries[i].data.clip.y0,
-					knockout_entries[i].data.clip.x1,
-					knockout_entries[i].data.clip.y1);
+					&knockout_entries[i].data.clip);
 			break;
 		case KNOCKOUT_PLOT_TEXT:
 			success &= plot.text(
@@ -584,10 +567,7 @@ bool knockout_plot_bitmap_recursive(struct knockout_box *box,
 		if (parent->child)
 			knockout_plot_bitmap_recursive(parent->child, entry);
 		else {
-			success &= plot.clip(parent->bbox.x0,
-					parent->bbox.y0,
-					parent->bbox.x1,
-					parent->bbox.y1);
+			success &= plot.clip(&parent->bbox);
 			success &= plot.bitmap(entry->data.bitmap.x,
 					entry->data.bitmap.y,
 					entry->data.bitmap.width,
@@ -608,12 +588,12 @@ bool knockout_plot_rectangle(int x0, int y0, int x1, int y1, const plot_style_t
 		/* filled draw */
 
 		/* get our bounds */
-		kx0 = (x0 > clip_x0_cur) ? x0 : clip_x0_cur;
-		ky0 = (y0 > clip_y0_cur) ? y0 : clip_y0_cur;
-		kx1 = (x1 < clip_x1_cur) ? x1 : clip_x1_cur;
-		ky1 = (y1 < clip_y1_cur) ? y1 : clip_y1_cur;
-		if ((kx0 > clip_x1_cur) || (kx1 < clip_x0_cur) ||
-		    (ky0 > clip_y1_cur) || (ky1 < clip_y0_cur))
+		kx0 = (x0 > clip_cur.x0) ? x0 : clip_cur.x0;
+		ky0 = (y0 > clip_cur.y0) ? y0 : clip_cur.y0;
+		kx1 = (x1 < clip_cur.x1) ? x1 : clip_cur.x1;
+		ky1 = (y1 < clip_cur.y1) ? y1 : clip_cur.y1;
+		if ((kx0 > clip_cur.x1) || (kx1 < clip_cur.x0) ||
+		    (ky0 > clip_cur.y1) || (ky1 < clip_cur.y0))
 			return true;
 
 		/* fills both knock out and get knocked out */
@@ -707,25 +687,18 @@ bool knockout_plot_path(const float *p, unsigned int n, colour fill,
 }
 
 
-bool knockout_plot_clip(int clip_x0, int clip_y0,
-		int clip_x1, int clip_y1)
+bool knockout_plot_clip(const struct rect *clip)
 {
-	if (clip_x1 < clip_x0 || clip_y0 > clip_y1) {
+	if (clip->x1 < clip->x0 || clip->y0 > clip->y1) {
 		LOG(("bad clip rectangle %i %i %i %i",
-				clip_x0, clip_y0, clip_x1, clip_y1));
+				clip->x0, clip->y0, clip->x1, clip->y1));
 		return false;
 	}
 
 	/* memorise clip for bitmap tiling */
-	clip_x0_cur = clip_x0;
-	clip_y0_cur = clip_y0;
-	clip_x1_cur = clip_x1;
-	clip_y1_cur = clip_y1;
-
-	knockout_entries[knockout_entry_cur].data.clip.x0 = clip_x0;
-	knockout_entries[knockout_entry_cur].data.clip.y0 = clip_y0;
-	knockout_entries[knockout_entry_cur].data.clip.x1 = clip_x1;
-	knockout_entries[knockout_entry_cur].data.clip.y1 = clip_y1;
+	clip_cur = *clip;
+
+	knockout_entries[knockout_entry_cur].data.clip = *clip;
 	knockout_entries[knockout_entry_cur].type = KNOCKOUT_PLOT_CLIP;
 	if (++knockout_entry_cur >= KNOCKOUT_ENTRIES)
 		knockout_plot_flush();
@@ -783,16 +756,16 @@ bool knockout_plot_bitmap(int x, int y, int width, int height,
 	int kx0, ky0, kx1, ky1;
 
 	/* get our bounds */
-	kx0 = clip_x0_cur;
-	ky0 = clip_y0_cur;
-	kx1 = clip_x1_cur;
-	ky1 = clip_y1_cur;
+	kx0 = clip_cur.x0;
+	ky0 = clip_cur.y0;
+	kx1 = clip_cur.x1;
+	ky1 = clip_cur.y1;
 	if (!(flags & BITMAPF_REPEAT_X)) {
 		if (x > kx0)
 			kx0 = x;
 		if (x + width < kx1)
 			kx1 = x + width;
-		if ((kx0 > clip_x1_cur) || (kx1 < clip_x0_cur))
+		if ((kx0 > clip_cur.x1) || (kx1 < clip_cur.x0))
 			return true;
 	}
 	if (!(flags & BITMAPF_REPEAT_Y)) {
@@ -800,7 +773,7 @@ bool knockout_plot_bitmap(int x, int y, int width, int height,
 			ky0 = y;
 		if (y + height < ky1)
 			ky1 = y + height;
-		if ((ky0 > clip_y1_cur) || (ky1 < clip_y0_cur))
+		if ((ky0 > clip_cur.y1) || (ky1 < clip_cur.y0))
 			return true;
 	}
 
@@ -827,7 +800,7 @@ bool knockout_plot_bitmap(int x, int y, int width, int height,
 	if ((++knockout_entry_cur >= KNOCKOUT_ENTRIES) ||
 			(++knockout_box_cur >= KNOCKOUT_BOXES))
 		knockout_plot_flush();
-	return knockout_plot_clip(clip_x0_cur, clip_y0_cur, clip_x1_cur, clip_y1_cur);
+	return knockout_plot_clip(&clip_cur);
 }
 
 bool knockout_plot_group_start(const char *name)
diff --git a/desktop/plotters.h b/desktop/plotters.h
index 076baf242..02735a15f 100644
--- a/desktop/plotters.h
+++ b/desktop/plotters.h
@@ -27,6 +27,7 @@
 #include "css/css.h"
 #include "content/content.h"
 #include "desktop/plot_style.h"
+#include "desktop/shape.h"
 
 struct bitmap;
 
@@ -96,7 +97,7 @@ typedef unsigned long bitmap_flags_t;
  */
 struct plotter_table {
 	/* clipping operations */
-	bool (*clip)(int x0, int y0, int x1, int y1);
+	bool (*clip)(const struct rect *clip);
 
         /* shape primatives */
 	bool (*arc)(int x, int y, int radius, int angle1, int angle2, const plot_style_t *pstyle);
diff --git a/desktop/save_pdf/pdf_plotters.c b/desktop/save_pdf/pdf_plotters.c
index f33070edb..847d6dafc 100644
--- a/desktop/save_pdf/pdf_plotters.c
+++ b/desktop/save_pdf/pdf_plotters.c
@@ -49,8 +49,7 @@
 static bool pdf_plot_rectangle(int x0, int y0, int x1, int y1, const plot_style_t *style);
 static bool pdf_plot_line(int x0, int y0, int x1, int y1, const plot_style_t *pstyle);
 static bool pdf_plot_polygon(const int *p, unsigned int n, const plot_style_t *style);
-static bool pdf_plot_clip(int clip_x0, int clip_y0,
-		int clip_x1, int clip_y1);
+static bool pdf_plot_clip(const struct rect *clip);
 static bool pdf_plot_text(int x, int y, const char *text, size_t length, 
 		const plot_font_style_t *fstyle);
 static bool pdf_plot_disc(int x, int y, int radius, const plot_style_t *style);
@@ -267,19 +266,19 @@ bool pdf_plot_polygon(const int *p, unsigned int n, const plot_style_t *style)
 
 
 /**here the clip is only queried */
-bool pdf_plot_clip(int clip_x0, int clip_y0, int clip_x1, int clip_y1)
+bool pdf_plot_clip(const struct rect *clip)
 {
 #ifdef PDF_DEBUG
-	LOG(("%d %d %d %d", clip_x0, clip_y0, clip_x1, clip_y1));
+	LOG(("%d %d %d %d", clip->x0, clip->y0, clip->x1, clip->y1));
 #endif
 
 	/*Normalize cllipping area - to prevent overflows.
 	  See comment in pdf_plot_fill.
 	*/
-	last_clip_x0 = min(max(clip_x0, 0), page_width);
-	last_clip_y0 = min(max(clip_y0, 0), page_height);
-	last_clip_x1 = min(max(clip_x1, 0), page_width);
-	last_clip_y1 = min(max(clip_y1, 0), page_height);
+	last_clip_x0 = min(max(clip->x0, 0), page_width);
+	last_clip_y0 = min(max(clip->y0, 0), page_height);
+	last_clip_x1 = min(max(clip->x1, 0), page_width);
+	last_clip_y1 = min(max(clip->y1, 0), page_height);
 
 	clip_update_needed = true;
 
diff --git a/desktop/textarea.c b/desktop/textarea.c
index a0dc860ba..5450dde64 100644
--- a/desktop/textarea.c
+++ b/desktop/textarea.c
@@ -777,7 +777,7 @@ void textarea_redraw(struct text_area *ta, int x, int y,
 	if (r.y1 > y + ta->vis_height)
 		r.y1 = y + ta->vis_height;
 
-	plot.clip(r.x0, r.y0, r.x1, r.y1);
+	plot.clip(&r);
 	plot.rectangle(r.x0, r.y0, r.x1, r.y1, &plot_style_fill_bg);
 	plot.rectangle(x, y,
 		       x + ta->vis_width - 1, y + ta->vis_height - 1,
@@ -787,7 +787,7 @@ void textarea_redraw(struct text_area *ta, int x, int y,
 		r.x0 = x + MARGIN_LEFT;
 	if (r.x1 > x + ta->vis_width - MARGIN_RIGHT)
 		r.x1 = x + ta->vis_width - MARGIN_RIGHT;
-	plot.clip(r.x0, r.y0, r.x1, r.y1);
+	plot.clip(&r);
 
 	if (line0 > 0)
 		c_pos = utf8_bounded_length(ta->text,
diff --git a/desktop/tree.c b/desktop/tree.c
index 7e303827d..9dc38c247 100644
--- a/desktop/tree.c
+++ b/desktop/tree.c
@@ -1577,7 +1577,7 @@ static void tree_draw_node_expansion_toggle(struct tree *tree,
  */
 static void tree_draw_node_element(struct tree *tree,
 		struct node_element *element, int tree_x, int tree_y,
-		struct rect clip)
+		const struct rect *clip)
 {
 
 	struct bitmap *bitmap = NULL;
@@ -1605,28 +1605,28 @@ static void tree_draw_node_element(struct tree *tree,
 				CONTENT_STATUS_READY ||
 				content_get_status(icon) ==
 				CONTENT_STATUS_DONE) &&
-				x + TREE_ICON_SIZE > clip.x0 &&
-				x < clip.x1) {
+				x + TREE_ICON_SIZE > clip->x0 &&
+				x < clip->x1) {
 			struct rect c;
 			/* Clip to image area */
 			c.x0 = x;
 			c.y0 = y + icon_inset;
 			c.x1 = x + TREE_ICON_SIZE;
 			c.y1 = y + icon_inset + TREE_ICON_SIZE;
-			if (c.x0 < clip.x0) c.x0 = clip.x0;
-			if (c.y0 < clip.y0) c.y0 = clip.y0;
-			if (c.x1 > clip.x1) c.x1 = clip.x1;
-			if (c.y1 > clip.y1) c.y1 = clip.y1;
+			if (c.x0 < clip->x0) c.x0 = clip->x0;
+			if (c.y0 < clip->y0) c.y0 = clip->y0;
+			if (c.x1 > clip->x1) c.x1 = clip->x1;
+			if (c.y1 > clip->y1) c.y1 = clip->y1;
 
 			if (c.x1 > c.x0 && c.y1 > c.y0) {
 				/* Valid clip rectangles only */
-				plot.clip(c.x0, c.y0, c.x1, c.y1);
+				plot.clip(&c);
 				content_redraw(icon , x, y + icon_inset,
 						TREE_ICON_SIZE, TREE_ICON_SIZE,
 						&c, 1, 0);
 
 				/* Restore previous clipping area */
-				plot.clip(clip.x0, clip.y0, clip.x1, clip.y1);
+				plot.clip(clip);
 			}
 		}
 
@@ -1635,7 +1635,7 @@ static void tree_draw_node_element(struct tree *tree,
 
 		/* fall through */
 	case NODE_ELEMENT_TEXT:
-		if (element->text == NULL || clip.x1 < x)
+		if (element->text == NULL || clip->x1 < x)
 			break;
 
 		if (element == tree->editing)
@@ -1720,7 +1720,7 @@ static void tree_draw_node(struct tree *tree, struct node *node,
 	}
 
 	/* Set up the clipping area */
-	plot.clip(clip.x0, clip.y0, clip.x1, clip.y1);
+	plot.clip(&clip);
 
 	/* Draw node's furniture */
 	if (!(tree->flags & TREE_NO_FURNITURE)) {
@@ -1772,11 +1772,12 @@ static void tree_draw_node(struct tree *tree, struct node *node,
 				element = element->next) {
 			/* Draw each element of expanded node */
 			tree_draw_node_element(tree, element, tree_x, tree_y,
-					clip);
+					&clip);
 		}
 	} else {
 		/* Draw main title element of node */
-		tree_draw_node_element(tree, &node->data, tree_x, tree_y, clip);
+		tree_draw_node_element(tree, &node->data, tree_x, tree_y,
+				&clip);
 	}
 }
 
@@ -1849,7 +1850,7 @@ void tree_draw(struct tree *tree, int x, int y,
 	clip.y0 = y + clip_y;
 	clip.x1 = clip.x0 + clip_width;
 	clip.y1 = clip.y0 + clip_height;
-	plot.clip(clip.x0, clip.y0, clip.x1, clip.y1);
+	plot.clip(&clip);
 
 	/* Flat fill extents of clipping area */
 	plot.rectangle(clip.x0, clip.y0, clip.x1, clip.y1,
diff --git a/framebuffer/framebuffer.c b/framebuffer/framebuffer.c
index bed356863..535f63c85 100644
--- a/framebuffer/framebuffer.c
+++ b/framebuffer/framebuffer.c
@@ -331,15 +331,15 @@ framebuffer_plot_path(const float *p,
 }
 
 static bool 
-framebuffer_plot_clip(int x0, int y0, int x1, int y1)
+framebuffer_plot_clip(const struct rect *clip)
 {
-	nsfb_bbox_t clip;
-	clip.x0 = x0;
-	clip.y0 = y0;
-	clip.x1 = x1;
-	clip.y1 = y1;
+	nsfb_bbox_t nsfb_clip;
+	nsfb_clip.x0 = clip->x0;
+	nsfb_clip.y0 = clip->y0;
+	nsfb_clip.x1 = clip->x1;
+	nsfb_clip.y1 = clip->y1;
 
-	return nsfb_plot_set_clip(nsfb, &clip);
+	return nsfb_plot_set_clip(nsfb, &nsfb_clip);
 }
 
 struct plotter_table plot = {
diff --git a/gtk/plotters.c b/gtk/plotters.c
index 460a65a6f..76273bd0e 100644
--- a/gtk/plotters.c
+++ b/gtk/plotters.c
@@ -133,17 +133,17 @@ static inline void nsgtk_set_dashed(void)
 }
 
 /** Set clipping area for subsequent plot operations. */
-static bool nsgtk_plot_clip(int clip_x0, int clip_y0, int clip_x1, int clip_y1)
+static bool nsgtk_plot_clip(const struct rect *clip)
 {
 	cairo_reset_clip(current_cr);
-	cairo_rectangle(current_cr, clip_x0, clip_y0,
-			clip_x1 - clip_x0, clip_y1 - clip_y0);
+	cairo_rectangle(current_cr, clip->x0, clip->y0,
+			clip->x1 - clip->x0, clip->y1 - clip->y0);
 	cairo_clip(current_cr);
 
-	cliprect.x = clip_x0;
-	cliprect.y = clip_y0;
-	cliprect.width = clip_x1 - clip_x0;
-	cliprect.height = clip_y1 - clip_y0;
+	cliprect.x = clip->x0;
+	cliprect.y = clip->y0;
+	cliprect.width = clip->x1 - clip->x0;
+	cliprect.height = clip->y1 - clip->y0;
 	gdk_gc_set_clip_rectangle(current_gc, &cliprect);
 
 	return true;
diff --git a/gtk/print.c b/gtk/print.c
index 5f518e266..1da89551a 100644
--- a/gtk/print.c
+++ b/gtk/print.c
@@ -169,17 +169,17 @@ static inline void nsgtk_print_set_dashed(void)
 }
 
 /** Set clipping area for subsequent plot operations. */
-static bool nsgtk_print_plot_clip(int clip_x0, int clip_y0, int clip_x1, int clip_y1)
+static bool nsgtk_print_plot_clip(struct rect *clip)
 {
 	LOG(("Clipping. x0: %i ;\t y0: %i ;\t x1: %i ;\t y1: %i",
-			clip_x0,clip_y0,clip_x1,clip_y1));	
+			clip->x0, clip->y0, clip->x1, clip->y1));	
 	
 	/* Normalize cllipping area - to prevent overflows.
 	 * See comment in pdf_plot_fill. */
-	clip_x0 = min(max(clip_x0, 0), settings->page_width);
-	clip_y0 = min(max(clip_y0, 0), settings->page_height);
-	clip_x1 = min(max(clip_x1, 0), settings->page_width);
-	clip_y1 = min(max(clip_y1, 0), settings->page_height);
+	int clip_x0 = min(max(clip->x0, 0), settings->page_width);
+	int clip_y0 = min(max(clip->y0, 0), settings->page_height);
+	int clip_x1 = min(max(clip->x1, 0), settings->page_width);
+	int clip_y1 = min(max(clip->y1, 0), settings->page_height);
 	
 	cairo_reset_clip(gtk_print_current_cr);
 	cairo_rectangle(gtk_print_current_cr, clip_x0, clip_y0,
diff --git a/gtk/scaffolding.c b/gtk/scaffolding.c
index 2fd865cb5..1a152ccd0 100644
--- a/gtk/scaffolding.c
+++ b/gtk/scaffolding.c
@@ -1486,6 +1486,7 @@ BUTTONHANDLER(history)
 static gboolean nsgtk_history_expose_event(GtkWidget *widget,
 		GdkEventExpose *event, gpointer g)
 {
+	struct rect clip;
 	struct gtk_history_window *hw = (struct gtk_history_window *)g;
 	struct browser_window *bw =
 			gui_window_get_browser_window(hw->g->top_level);
@@ -1499,10 +1500,11 @@ static gboolean nsgtk_history_expose_event(GtkWidget *widget,
 	plot = nsgtk_plotters;
 	nsgtk_plot_set_scale(1.0);
 
-	plot.clip(event->area.x,
-		  event->area.y,
-		  event->area.x + event->area.width,
-		  event->area.y + event->area.height);
+	clip.x0 = event->area.x;
+	clip.y0 = event->area.y;
+	clip.x1 = event->area.x + event->area.width;
+	clip.y1 = event->area.y + event->area.height;
+	plot.clip(&clip);
 
 	history_redraw(bw->history);
 
diff --git a/gtk/thumbnail.c b/gtk/thumbnail.c
index f0a25ce30..de359535b 100644
--- a/gtk/thumbnail.c
+++ b/gtk/thumbnail.c
@@ -106,7 +106,7 @@ bool thumbnail_create(hlcache_handle *content, struct bitmap *bitmap,
 #endif
 	plot.rectangle(0, 0, cwidth, cwidth, plot_style_fill_white);
 
-	plot.clip(clip.x0, clip.y0, clip.x1, clip.y1);
+	plot.clip(&clip);
 
 	/* render the content */
 	content_redraw(content, 0, 0, content_get_width(content), 
diff --git a/render/form.c b/render/form.c
index 8c54b23d5..6c703692a 100644
--- a/render/form.c
+++ b/render/form.c
@@ -975,7 +975,7 @@ void form_free_select_menu(struct form_control *control)
  * \return		true on success, false otherwise
  */
 bool form_redraw_select_menu(struct form_control *control, int x, int y,
-		float scale, int clip_x0, int clip_y0, int clip_x1, int clip_y1)
+		float scale, const struct rect *clip)
 {
 	struct box *box;
 	struct form_select_menu *menu = control->data.select.menu;
@@ -989,11 +989,7 @@ bool form_redraw_select_menu(struct form_control *control, int x, int y,
 	int i;
 	int scroll;
 	int x_cp, y_cp;
-	struct rect clip;
-	clip.x0 = clip_x0;
-	clip.y0 = clip_y0;
-	clip.x1 = clip_x1;
-	clip.y1 = clip_y1;
+	struct rect r;
 	
 	box = control->box;
 	
@@ -1028,8 +1024,12 @@ bool form_redraw_select_menu(struct form_control *control, int x, int y,
 	x1 = x + width - 1;
 	y1 = y + height - 1;
 	scrollbar_x = x1 - scrollbar_width;
-	
-	if (!plot.clip(x0, y0, x1 + 1, y1 + 1))
+
+	r.x0 = x0;
+	r.y0 = y0;
+	r.x1 = x1 + 1;
+	r.y1 = y1 + 1;
+	if (!plot.clip(&r))
 		return false;
 	if (!plot.rectangle(x0, y0, x1, y1 ,plot_style_stroke_darkwbasec))
 		return false;
@@ -1041,7 +1041,11 @@ bool form_redraw_select_menu(struct form_control *control, int x, int y,
 	y1 = y1 - SELECT_BORDER_WIDTH;
 	height = height - 2 * SELECT_BORDER_WIDTH;
 
-	if (!plot.clip(x0, y0, x1 + 1, y1 + 1))
+	r.x0 = x0;
+	r.y0 = y0;
+	r.x1 = x1 + 1;
+	r.y1 = y1 + 1;
+	if (!plot.clip(&r))
 		return false;
 	if (!plot.rectangle(x0, y0, x1 + 1, y1 + 1,
 			plot_style_fill_lightwbasec))
@@ -1084,7 +1088,7 @@ bool form_redraw_select_menu(struct form_control *control, int x, int y,
 	if (!scroll_redraw(menu->scroll,
 			x_cp + menu->width - SCROLLBAR_WIDTH,
       			y_cp,
-			&clip, scale))
+			clip, scale))
 		return false;
 	
 	return true;
@@ -1103,7 +1107,7 @@ bool form_redraw_select_menu(struct form_control *control, int x, int y,
  * \return		true if inside false otherwise
  */
 bool form_clip_inside_select_menu(struct form_control *control, float scale,
-		int clip_x0, int clip_y0, int clip_x1, int clip_y1)
+		const struct rect *clip)
 {
 	struct form_select_menu *menu = control->data.select.menu;
 	int width, height;
@@ -1117,8 +1121,8 @@ bool form_clip_inside_select_menu(struct form_control *control, float scale,
 		height *= scale;
 	}
 	
-	if (clip_x0 >= 0 && clip_x1 <= width &&
-			clip_y0 >= 0 && clip_y1 <= height)
+	if (clip->x0 >= 0 && clip->x1 <= width &&
+			clip->y0 >= 0 && clip->y1 <= height)
 		return true;
 
 	return false;
diff --git a/render/form.h b/render/form.h
index 9da24b8b9..a6cda0a99 100644
--- a/render/form.h
+++ b/render/form.h
@@ -161,10 +161,9 @@ void form_select_menu_callback(void *client_data,
 		int x, int y, int width, int height);
 void form_free_select_menu(struct form_control *control);
 bool form_redraw_select_menu(struct form_control *control, int x, int y,
-		float scale,
-  		int clip_x0, int clip_y0, int clip_x1, int clip_y1);
+		float scale, const struct rect *clip);
 bool form_clip_inside_select_menu(struct form_control *control, float scale,
-		int clip_x0, int clip_y0, int clip_x1, int clip_y1);
+		const struct rect *clip);
 const char *form_select_mouse_action(struct form_control *control,
 		browser_mouse_state mouse, int x, int y);
 void form_select_mouse_drag_end(struct form_control *control,
diff --git a/render/html_redraw.c b/render/html_redraw.c
index 8468d3007..2c355c67c 100644
--- a/render/html_redraw.c
+++ b/render/html_redraw.c
@@ -141,12 +141,12 @@ bool html_redraw(struct content *c, int x, int y,
 		/* check if the redraw rectangle is completely inside of the
 		   select menu */
 		select_only = form_clip_inside_select_menu(control, scale,
-				clip->x0, clip->y0, clip->x1, clip->y1);
+				clip);
 	}
 	
 	if (!select_only) {
 		/* clear to background colour */
-		result = plot.clip(clip->x0, clip->y0, clip->x1, clip->y1);
+		result = plot.clip(clip);
 	
 		if (c->data.html.background_colour != NS_TRANSPARENT)
 			pstyle_fill_bg.fill_colour =
@@ -170,8 +170,7 @@ bool html_redraw(struct content *c, int x, int y,
 		result &= form_redraw_select_menu(
 				current_redraw_browser->visible_select_menu,
 				x + menu_x, y + menu_y,
-    				current_redraw_browser->scale,
-				clip->x0, clip->y0, clip->x1, clip->y1);
+    				current_redraw_browser->scale, clip);
 	}
 	
 	if (want_knockout)
@@ -412,7 +411,7 @@ bool html_redraw_box(struct box *box, int x_parent, int y_parent,
 			/* not an error */
 			return ((!plot.group_end) || (plot.group_end()));
 		/* clip to it */
-		if (!plot.clip(r.x0, r.y0, r.x1, r.y1))
+		if (!plot.clip(&r))
 			return false;
 	} else {
 		/* clip box unchanged */
@@ -470,7 +469,7 @@ bool html_redraw_box(struct box *box, int x_parent, int y_parent,
 					&current_background_color, bg_box))
 				return false;
 			/* restore previous graphics window */
-			if (!plot.clip(r.x0, r.y0, r.x1, r.y1))
+			if (!plot.clip(&r))
 				return false;
 		}
 	}
@@ -544,7 +543,7 @@ bool html_redraw_box(struct box *box, int x_parent, int y_parent,
 						&current_background_color))
 					return false;
 				/* restore previous graphics window */
-				if (!plot.clip(r.x0, r.y0, r.x1, r.y1))
+				if (!plot.clip(&r))
 					return false;
 				if (!html_redraw_inline_borders(box, b, r,
 						scale, first, false))
@@ -576,7 +575,7 @@ bool html_redraw_box(struct box *box, int x_parent, int y_parent,
 				first, true, &current_background_color))
 			return false;
 		/* restore previous graphics window */
-		if (!plot.clip(r.x0, r.y0, r.x1, r.y1))
+		if (!plot.clip(&r))
 			return false;
 		if (!html_redraw_inline_borders(box, b, r, scale, first, true))
 			return false;
@@ -639,7 +638,7 @@ bool html_redraw_box(struct box *box, int x_parent, int y_parent,
 			return ((!plot.group_end) || (plot.group_end()));
 		if (box->type == BOX_BLOCK || box->type == BOX_INLINE_BLOCK ||
 				box->type == BOX_TABLE_CELL || box->object) {
-			if (!plot.clip(r.x0, r.y0, r.x1, r.y1))
+			if (!plot.clip(&r))
 				return false;
 		}
 	}
@@ -734,7 +733,7 @@ bool html_redraw_box(struct box *box, int x_parent, int y_parent,
 
 	if (box->type == BOX_BLOCK || box->type == BOX_INLINE_BLOCK ||
 			box->type == BOX_TABLE_CELL || box->object)
-		if (!plot.clip(clip.x0, clip.y0, clip.x1, clip.y1))
+		if (!plot.clip(&clip))
 			return false;
 
 	return ((!plot.group_end) || (plot.group_end()));
@@ -875,6 +874,7 @@ bool text_redraw(const char *utf8_text, size_t utf8_len,
 
 		/* \todo make search terms visible within selected text */
 		if (highlighted) {
+			struct rect r;
 			unsigned endtxt_idx = end_idx;
 			bool clip_changed = false;
 			bool text_visible = true;
@@ -936,8 +936,11 @@ bool text_redraw(const char *utf8_text, size_t utf8_len,
 				int px1 = min(x + endx, clip->x1);
 
 				if (px0 < px1) {
-					if (!plot.clip(px0, clip->y0, px1,
-							clip->y1))
+					r.x0 = px0;
+					r.y0 = clip->y0;
+					r.x1 = px1;
+					r.y1 = clip->y1;
+					if (!plot.clip(&r))
 						return false;
 					clip_changed = true;
 				} else {
@@ -961,8 +964,11 @@ bool text_redraw(const char *utf8_text, size_t utf8_len,
 				int px0 = max(x + endx, clip->x0);
 				if (px0 < clip->x1) {
 
-					if (!plot.clip(px0, clip->y0,
-							clip->x1, clip->y1))
+					r.x0 = px0;
+					r.y0 = clip->y0;
+					r.x1 = clip->x1;
+					r.y1 = clip->y1;
+					if (!plot.clip(&r))
 						return false;
 
 					clip_changed = true;
@@ -976,8 +982,7 @@ bool text_redraw(const char *utf8_text, size_t utf8_len,
 			}
 
 			if (clip_changed &&
-				!plot.clip(clip->x0, clip->y0,
-						clip->x1, clip->y1))
+				!plot.clip(clip))
 				return false;
 		}
 	}
@@ -2172,8 +2177,7 @@ bool html_redraw_background(int x, int y, struct box *box, float scale,
 			}
 			/* valid clipping rectangles only */
 			if ((clip.x0 < clip.x1) && (clip.y0 < clip.y1)) {
-				if (!plot.clip(clip.x0, clip.y0,
-						clip.x1, clip.y1))
+				if (!plot.clip(&clip))
 					return false;
 				if (!content_redraw_tiled(
 						background->background, x, y,
@@ -2314,8 +2318,7 @@ bool html_redraw_inline_background(int x, int y, struct box *box, float scale,
 		}
 		/* valid clipping rectangles only */
 		if ((clip.x0 < clip.x1) && (clip.y0 < clip.y1)) {
-			if (!plot.clip(clip.x0, clip.y0,
-					clip.x1, clip.y1))
+			if (!plot.clip(&clip))
 				return false;
 			if (!content_redraw_tiled(box->background, x, y,
 					ceilf(width * scale),
diff --git a/riscos/debugwin.c b/riscos/debugwin.c
index dd7a134b4..c32731a71 100644
--- a/riscos/debugwin.c
+++ b/riscos/debugwin.c
@@ -61,11 +61,10 @@ enum align {
 static plot_font_style_t fstyle;
 static plot_style_t style;
 
-static void debugwin_redraw(int clip_x0, int clip_y0, int clip_x1, int clip_y1);
+static void debugwin_redraw(const struct rect *clip);
 static void debugwin_get_size(int *width, int *height);
 static bool debugwin_render_cell(int x, int y, int width, int height,
-		const char *text, enum align align, int clip_x0, int clip_y0,
-		int clip_x1, int clip_y1);
+		const char *text, enum align align, const struct rect *clip);
 #endif
 
 
@@ -152,21 +151,21 @@ void ro_gui_debugwin_redraw(wimp_draw *redraw)
 		return;
 	}
 	while (more) {
-		int clip_x0, clip_y0, clip_x1, clip_y1;
+		struct rect clip;
 
 		/* Sep plot origin */
 		ro_plot_origin_x = redraw->box.x0 - redraw->xscroll;
 		ro_plot_origin_y = redraw->box.y1 - redraw->yscroll;
 
 		/* Set clip rectangle */
-		clip_x0 = (redraw->clip.x0 - ro_plot_origin_x) / 2; /* left   */
-		clip_y0 = (ro_plot_origin_y - redraw->clip.y1) / 2; /* top    */
-		clip_x1 = (redraw->clip.x1 - ro_plot_origin_x) / 2; /* right  */
-		clip_y1 = (ro_plot_origin_y - redraw->clip.y0) / 2; /* bottom */
-		plot.clip(clip_x0, clip_y0, clip_x1, clip_y1);
+		clip.x0 = (redraw->clip.x0 - ro_plot_origin_x) / 2; /* left   */
+		clip.y0 = (ro_plot_origin_y - redraw->clip.y1) / 2; /* top    */
+		clip.x1 = (redraw->clip.x1 - ro_plot_origin_x) / 2; /* right  */
+		clip.y1 = (ro_plot_origin_y - redraw->clip.y0) / 2; /* bottom */
+		plot.clip(&clip);
 
 		/* Render the content debug table */
-		debugwin_redraw(clip_x0, clip_y0, clip_x1, clip_y1);
+		debugwin_redraw(&clip);
 
 		error = xwimp_get_rectangle(redraw, &more);
 		if (error) {
@@ -179,7 +178,7 @@ void ro_gui_debugwin_redraw(wimp_draw *redraw)
 }
 
 
-void debugwin_redraw(int clip_x0, int clip_y0, int clip_x1, int clip_y1)
+void debugwin_redraw(const struct rect *clip)
 {
 	char s[40];
 	int y, x, w;
@@ -225,38 +224,31 @@ void debugwin_redraw(int clip_x0, int clip_y0, int clip_x1, int clip_y1)
 	x = 0;
 	w = w_url;
 	debugwin_render_cell(x, y, w, DEBUGWIN_TEXT_HEIGHT,
-			"url", DEBUGWIN_CENTRE, clip_x0, clip_y0,
-			clip_x1, clip_y1);
+			"url", DEBUGWIN_CENTRE, clip);
 	x += w + 1;
 	w = w_type;
 	debugwin_render_cell(x, y, w, DEBUGWIN_TEXT_HEIGHT,
-			"type", DEBUGWIN_CENTRE, clip_x0, clip_y0,
-			clip_x1, clip_y1);
+			"type", DEBUGWIN_CENTRE, clip);
 	x += w + 1;
 	w = w_fresh;
 	debugwin_render_cell(x, y, w, DEBUGWIN_TEXT_HEIGHT,
-			"fresh", DEBUGWIN_CENTRE, clip_x0, clip_y0,
-			clip_x1, clip_y1);
+			"fresh", DEBUGWIN_CENTRE, clip);
 	x += w + 1;
 	w = w_mime_type;
 	debugwin_render_cell(x, y, w, DEBUGWIN_TEXT_HEIGHT,
-			"mime-type", DEBUGWIN_CENTRE, clip_x0, clip_y0,
-			clip_x1, clip_y1);
+			"mime-type", DEBUGWIN_CENTRE, clip);
 	x += w + 1;
 	w = w_users;
 	debugwin_render_cell(x, y, w, DEBUGWIN_TEXT_HEIGHT,
-			"users", DEBUGWIN_CENTRE, clip_x0, clip_y0,
-			clip_x1, clip_y1);
+			"users", DEBUGWIN_CENTRE, clip);
 	x += w + 1;
 	w = w_status;
 	debugwin_render_cell(x, y, w, DEBUGWIN_TEXT_HEIGHT,
-			"status", DEBUGWIN_CENTRE, clip_x0, clip_y0,
-			clip_x1, clip_y1);
+			"status", DEBUGWIN_CENTRE, clip);
 	x += w + 1;
 	w = w_size;
 	debugwin_render_cell(x, y, w, DEBUGWIN_TEXT_HEIGHT,
-			"size", DEBUGWIN_CENTRE, clip_x0, clip_y0,
-			clip_x1, clip_y1);
+			"size", DEBUGWIN_CENTRE, clip);
 
 	/* Move down to next row */
 	y += DEBUGWIN_TEXT_HEIGHT + 2 * DEBUGWIN_CELL_PADDING + 1;
@@ -273,20 +265,19 @@ void debugwin_redraw(int clip_x0, int clip_y0, int clip_x1, int clip_y1)
 		x = 0;
 		w = w_url;
 		debugwin_render_cell(x, y, w, DEBUGWIN_TEXT_HEIGHT,
-				content->url, DEBUGWIN_RIGHT, clip_x0, clip_y0,
-				clip_x1, clip_y1);
+				content->url, DEBUGWIN_RIGHT, clip);
 		/* Create Type cell */
 		x += w + 1;
 		w = w_type;
 		debugwin_render_cell(x, y, w, DEBUGWIN_TEXT_HEIGHT,
 				content_type_name[content->type], DEBUGWIN_LEFT,
-				clip_x0, clip_y0, clip_x1, clip_y1);
+				clip);
 		/* Create cell for showing wheher content is fresh */
 		x += w + 1;
 		w = w_fresh;
 		debugwin_render_cell(x, y, w, DEBUGWIN_TEXT_HEIGHT,
 				content->fresh ? "yes" : "no", DEBUGWIN_LEFT,
-				clip_x0, clip_y0, clip_x1, clip_y1);
+				clip);
 		/* Create Mime-type cell */
 		x += w + 1;
 		w = w_mime_type;
@@ -302,15 +293,13 @@ void debugwin_redraw(int clip_x0, int clip_y0, int clip_x1, int clip_y1)
 		x += w + 1;
 		w = w_users;
 		debugwin_render_cell(x, y, w, DEBUGWIN_TEXT_HEIGHT,
-				s, DEBUGWIN_RIGHT, clip_x0, clip_y0,
-				clip_x1, clip_y1);
+				s, DEBUGWIN_RIGHT, clip);
 		/* Create Status cell */
 		x += w + 1;
 		w = w_status;
 		debugwin_render_cell(x, y, w, DEBUGWIN_TEXT_HEIGHT,
 				content_status_name[content->status],
-				DEBUGWIN_LEFT, clip_x0, clip_y0,
-				clip_x1, clip_y1);
+				DEBUGWIN_LEFT, clip);
 		/* Create Size cell */
 		talloc_size = talloc_total_size(content);
 		snprintf(s, sizeof s, "%u+%u= %u", content->size, talloc_size,
@@ -318,8 +307,7 @@ void debugwin_redraw(int clip_x0, int clip_y0, int clip_x1, int clip_y1)
 		x += w + 1;
 		w = w_size;
 		debugwin_render_cell(x, y, w, DEBUGWIN_TEXT_HEIGHT,
-				s, DEBUGWIN_RIGHT, clip_x0, clip_y0,
-				clip_x1, clip_y1);
+				s, DEBUGWIN_RIGHT, clip);
 
 		/* Keep running total of size used */
 		size += content->size + talloc_size;
@@ -332,7 +320,7 @@ void debugwin_redraw(int clip_x0, int clip_y0, int clip_x1, int clip_y1)
 	/* Show total size */
 	debugwin_render_cell(DEBUGWIN_WINDOW_WIDTH - w_size, y,
 			w_size, DEBUGWIN_TEXT_HEIGHT, s, DEBUGWIN_RIGHT,
-			clip_x0, clip_y0, clip_x1, clip_y1);
+			clip);
 
 	/* Heading cell for total size */
 	fstyle.weight = 900;
@@ -342,7 +330,7 @@ void debugwin_redraw(int clip_x0, int clip_y0, int clip_x1, int clip_y1)
 	debugwin_render_cell(0, y,
 			DEBUGWIN_WINDOW_WIDTH - w_size - 1,
 			DEBUGWIN_TEXT_HEIGHT, "total size:", DEBUGWIN_RIGHT,
-			clip_x0, clip_y0, clip_x1, clip_y1);
+			clip);
 
 //	if (want_knockout)
 //		knockout_plot_end();
@@ -369,24 +357,25 @@ void debugwin_get_size(int *width, int *height)
 
 
 bool debugwin_render_cell(int x, int y, int width, int height,
-		const char *text, enum align align, int clip_x0, int clip_y0,
-		int clip_x1, int clip_y1)
+		const char *text, enum align align, const struct rect *clip)
 {
 	int text_width;
 	size_t length;
+	struct rect r;
 
 	height += 2 * DEBUGWIN_CELL_PADDING;
 
 	/* Return if the rectangle is completely outside the clip rectangle */
-	if (clip_y1 < y || y + height < clip_y0 ||
-			clip_x1 < x || x + width < clip_x0)
+	if (clip->y1 < y || y + height < clip->y0 ||
+			clip->x1 < x || x + width < clip->x0)
 		return true;
 
 	/* Clip to intersection of clip rectangle and cell */
-	if (!plot.clip( (x < clip_x0) ? clip_x0 : x,
-			(y < clip_y0) ? clip_y0 : y,
-			(clip_x1 < x + width)  ? clip_x1 : x + width,
-			(clip_y1 < y + height) ? clip_y1 : y + height))
+	r.x0 = (x < clip->x0) ? clip->x0 : x;
+	r.y0 = (y < clip->y0) ? clip->y0 : y;
+	r.x1 = (clip->x1 < x + width)  ? clip->x1 : x + width;
+	r.y1 = (clip->y1 < y + height) ? clip->y1 : y + height);
+	if (!plot.clip(&r))
 		return false;
 
 	/* Plot cell background */
@@ -425,7 +414,7 @@ bool debugwin_render_cell(int x, int y, int width, int height,
 		return false;
 
 	/* Restore previous clip rectangle */
-	if (!plot.clip(clip_x0, clip_y0, clip_x1, clip_y1))
+	if (!plot.clip(clip))
 		return false;
 
 	return true;
diff --git a/riscos/gui/progress_bar.c b/riscos/gui/progress_bar.c
index bee9581aa..5c90195ad 100644
--- a/riscos/gui/progress_bar.c
+++ b/riscos/gui/progress_bar.c
@@ -468,7 +468,7 @@ void ro_gui_progress_bar_redraw_window(wimp_draw *redraw,
 {
 	os_error *error;
 	osbool more = true;
-	int clip_x0 = 0, clip_y0 = 0, clip_x1 = 0, clip_y1 = 0;
+	struct rect clip;
 	int progress_ymid;
 
 	/* initialise the plotters */
@@ -492,25 +492,25 @@ void ro_gui_progress_bar_redraw_window(wimp_draw *redraw,
 					redraw->box.y0 + pb->icon_y0,
 					tinct_ERROR_DIFFUSE);
 		if (!pb->icon_obscured) {
-		  	clip_x0 = max(redraw->clip.x0,
+		  	clip.x0 = max(redraw->clip.x0,
 		  			redraw->box.x0 + pb->visible.x0) >> 1;
-			clip_y0 = -min(redraw->clip.y1,
+			clip.y0 = -min(redraw->clip.y1,
 		  			redraw->box.y0 + pb->visible.y1) >> 1;
-			clip_x1 = min(redraw->clip.x1,
+			clip.x1 = min(redraw->clip.x1,
 					redraw->box.x0 + pb->visible.x1) >> 1;
-		  	clip_y1 = -max(redraw->clip.y0,
+		  	clip.y1 = -max(redraw->clip.y0,
 					redraw->box.y0 + pb->visible.y0) >> 1;
-		  	if ((clip_x0 < clip_x1) && (clip_y0 < clip_y1)) {
+		  	if ((clip.x0 < clip.x1) && (clip.y0 < clip.y1)) {
 				if (progress_icon) {
-			  		plot.clip(clip_x0, clip_y0, clip_x1, clip_y1);
+			  		plot.clip(&clip);
 					_swix(Tinct_Plot, _IN(2) | _IN(3) | _IN(4) | _IN(7),
 							progress_icon,
 							redraw->box.x0 - pb->offset,
 							progress_ymid - progress_height,
 							tinct_FILL_HORIZONTALLY);
 				} else {
-				  	plot.rectangle(clip_x0, clip_y0, 
-						       clip_x1, clip_y1,
+				  	plot.rectangle(clip.x0, clip.y0, 
+						       clip.x1, clip.y1,
 						       plot_style_fill_red);
 			  	}
 			}
diff --git a/riscos/plotters.c b/riscos/plotters.c
index 1323835d0..8d489fc0f 100644
--- a/riscos/plotters.c
+++ b/riscos/plotters.c
@@ -41,8 +41,7 @@ static bool ro_plot_draw_path(const draw_path * const path, int width,
 static bool ro_plot_polygon(const int *p, unsigned int n, const plot_style_t *style);
 static bool ro_plot_path(const float *p, unsigned int n, colour fill, float width,
 		colour c, const float transform[6]);
-static bool ro_plot_clip(int clip_x0, int clip_y0,
-		int clip_x1, int clip_y1);
+static bool ro_plot_clip(const struct rect *clip);
 static bool ro_plot_text(int x, int y, const char *text, size_t length, 
 		const plot_font_style_t *fstyle);
 static bool ro_plot_disc(int x, int y, int radius, const plot_style_t *style);
@@ -356,16 +355,15 @@ error:
 
 
 
-bool ro_plot_clip(int clip_x0, int clip_y0,
-		int clip_x1, int clip_y1)
+bool ro_plot_clip(const struct rect *clip)
 {
 	os_error *error;
 	char buf[12];
 
-	clip_x0 = ro_plot_origin_x + clip_x0 * 2;
-	clip_y0 = ro_plot_origin_y - clip_y0 * 2 - 1;
-	clip_x1 = ro_plot_origin_x + clip_x1 * 2 - 1;
-	clip_y1 = ro_plot_origin_y - clip_y1 * 2;
+	int clip_x0 = ro_plot_origin_x + clip->x0 * 2;
+	int clip_y0 = ro_plot_origin_y - clip->y0 * 2 - 1;
+	int clip_x1 = ro_plot_origin_x + clip->x1 * 2 - 1;
+	int clip_y1 = ro_plot_origin_y - clip->y1 * 2;
 
 	if (clip_x1 < clip_x0 || clip_y0 < clip_y1) {
 		LOG(("bad clip rectangle %i %i %i %i",
diff --git a/riscos/print.c b/riscos/print.c
index 575990f27..1a66e7e12 100644
--- a/riscos/print.c
+++ b/riscos/print.c
@@ -103,8 +103,7 @@ static const char *print_declare_fonts(hlcache_handle *h);
 static bool print_fonts_plot_rectangle(int x0, int y0, int x1, int y1, const plot_style_t *style);
 static bool print_fonts_plot_line(int x0, int y0, int x1, int y1, const plot_style_t *style);
 static bool print_fonts_plot_polygon(const int *p, unsigned int n, const plot_style_t *style);
-static bool print_fonts_plot_clip(int clip_x0, int clip_y0,
-		int clip_x1, int clip_y1);
+static bool print_fonts_plot_clip(const struct rect *clip);
 static bool print_fonts_plot_text(int x, int y, const char *text, size_t length,
 		const plot_font_style_t *fstyle);
 static bool print_fonts_plot_disc(int x, int y, int radius, const plot_style_t *style);
@@ -872,8 +871,7 @@ bool print_fonts_plot_polygon(const int *p, unsigned int n, const plot_style_t *
 }
 
 
-bool print_fonts_plot_clip(int clip_x0, int clip_y0,
-		int clip_x1, int clip_y1)
+bool print_fonts_plot_clip(const struct rect *clip)
 {
 	return true;
 }
diff --git a/riscos/save_draw.c b/riscos/save_draw.c
index 5fa93e4f7..765fb5c3b 100644
--- a/riscos/save_draw.c
+++ b/riscos/save_draw.c
@@ -44,8 +44,7 @@ static bool ro_save_draw_line(int x0, int y0, int x1, int y1, const plot_style_t
 static bool ro_save_draw_polygon(const int *p, unsigned int n, const plot_style_t *style);
 static bool ro_save_draw_path(const float *p, unsigned int n, colour fill,
 		float width, colour c, const float transform[6]);
-static bool ro_save_draw_clip(int clip_x0, int clip_y0,
-		int clip_x1, int clip_y1);
+static bool ro_save_draw_clip(const struct rect *clip);
 static bool ro_save_draw_text(int x, int y, const char *text, size_t length, 
 		const plot_font_style_t *fstyle);
 static bool ro_save_draw_disc(int x, int y, int radius, const plot_style_t *style);
@@ -347,8 +346,7 @@ bool ro_save_draw_path(const float *p, unsigned int n, colour fill,
 
 
 
-bool ro_save_draw_clip(int clip_x0, int clip_y0,
-		int clip_x1, int clip_y1)
+bool ro_save_draw_clip(const struct rect *clip)
 {
 	return true;
 }
diff --git a/riscos/treeview.c b/riscos/treeview.c
index 7cf711677..afd636519 100644
--- a/riscos/treeview.c
+++ b/riscos/treeview.c
@@ -358,6 +358,7 @@ void ro_treeview_redraw_loop(wimp_draw *redraw, ro_treeview *tv, osbool more)
 		ro_plot_origin_y = redraw->box.y1 - redraw->yscroll;
 
 		if (tv != NULL && tv->tree != NULL) {
+			struct rect clip;
 			tree_draw(tv->tree, tv->origin.x/2, -(tv->origin.y/2),
 					(redraw->clip.x0
 					-(ro_plot_origin_x+tv->origin.x))/2,
@@ -367,11 +368,11 @@ void ro_treeview_redraw_loop(wimp_draw *redraw, ro_treeview *tv, osbool more)
 					(redraw->clip.y1 - redraw->clip.y0)/2);
 
 			/* Put the graphcis window back how the Wimp set it. */
-
-			plot.clip((redraw->clip.x0 - ro_plot_origin_x)/2,
-					(ro_plot_origin_y - redraw->clip.y1)/2,
-					(redraw->clip.x1 - ro_plot_origin_x)/2,
-					(ro_plot_origin_y - redraw->clip.y0)/2);
+			clip.x0 = (redraw->clip.x0 - ro_plot_origin_x) / 2;
+			clip.y0 = (ro_plot_origin_y - redraw->clip.y1) / 2;
+			clip.x1 = (redraw->clip.x1 - ro_plot_origin_x) / 2;
+			clip.y1 = (ro_plot_origin_y - redraw->clip.y0) / 2;
+			plot.clip(&clip);
 	 	}
 
 		error = xwimp_get_rectangle(redraw, &more);
diff --git a/windows/plot.c b/windows/plot.c
index 050bf6136..2e21ae1fd 100644
--- a/windows/plot.c
+++ b/windows/plot.c
@@ -52,17 +52,16 @@ static float nsws_plot_scale = 1.0;
 
 static RECT plot_clip; /* currently set clipping rectangle */
 
-static bool clip(int x0, int y0, int x1, int y1)
+static bool clip(const struct rect *clip)
 {
-
 #if NSWS_PLOT_DEBUG
-	LOG(("clip %d,%d to %d,%d", x0, y0, x1, y1));
+	LOG(("clip %d,%d to %d,%d", clip->x0, clip->y0, clip->x1, clip->y1));
 #endif
 
-	plot_clip.left = x0;
-	plot_clip.top = y0;
-	plot_clip.right = x1 + 1; /* rectangle co-ordinates are exclusive */
-	plot_clip.bottom = y1 + 1; /* rectangle co-ordinates are exclusive */
+	plot_clip.left = clip->x0;
+	plot_clip.top = clip->y0;
+	plot_clip.right = clip->x1 + 1; /* co-ordinates are exclusive */
+	plot_clip.bottom = clip->y1 + 1; /* co-ordinates are exclusive */
 
 	return true;
 }
-- 
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