From bde04d10347414251b40af574d1bc94962d23a5a Mon Sep 17 00:00:00 2001
From: Michael Drake <tlsa@netsurf-browser.org>
Date: Wed, 1 Aug 2012 12:51:30 +0100
Subject: Add support for offset mouse pointer hotspots.

---
 include/cursor.h         |  2 ++
 include/libnsfb_cursor.h | 21 ++++++++++++++-------
 src/cursor.c             | 26 ++++++++++++++++++++++----
 src/surface/sdl.c        |  7 ++++++-
 4 files changed, 44 insertions(+), 12 deletions(-)

diff --git a/include/cursor.h b/include/cursor.h
index e3a8a04..076e6c9 100644
--- a/include/cursor.h
+++ b/include/cursor.h
@@ -20,6 +20,8 @@ struct nsfb_cursor_s {
     int bmp_width;
     int bmp_height;
     int bmp_stride;
+    int hotspot_x;
+    int hotspot_y;
 
     /* current saved image */
     nsfb_bbox_t savloc;
diff --git a/include/libnsfb_cursor.h b/include/libnsfb_cursor.h
index 4f36793..525bd83 100644
--- a/include/libnsfb_cursor.h
+++ b/include/libnsfb_cursor.h
@@ -17,15 +17,22 @@ bool nsfb_cursor_init(nsfb_t *nsfb);
 
 /** Set cursor parameters.
  *
- * Set a cursor, the cursor will be shown at the specified location and
- * size. The pixel data may be referenced untill the cursor is altered or
- * cleared
+ * Set a cursor bitmap, the cursor will be shown at the location set by
+ * nsfb_cursor_loc_set. The pixel data may be referenced untill the cursor
+ * is altered or cleared
  *
- * @param nsfb The frambuffer context.
- * @param loc The location of the cursor
- * @param pixel The pixel data for the cursor 
+ * @param nsfb       The frambuffer context
+ * @param pixel      The cursor bitmap data
+ * @param bmp_width  The width of the cursor bitmap
+ * @param bmp_height The height of the cursor bitmap
+ * @param bmp_stride The cursor bitmap's row stride
+ * @param hotspot_x  Coordinate within cursor image to place over cursor loc
+ * @param hotspot_y  Coordinate within cursor image to place over cursor loc
+ *
+ * (hot_spot_x, hot_spot_y) is from top left.  (0, 0) means top left pixel of
+ * cursor bitmap is to be rendered over the cursor location.
  */
-bool nsfb_cursor_set(nsfb_t *nsfb, const nsfb_colour_t *pixel, int bmp_width, int bmp_height, int bmp_stride);
+bool nsfb_cursor_set(nsfb_t *nsfb, const nsfb_colour_t *pixel, int bmp_width, int bmp_height, int bmp_stride, int hotspot_x, int hotspot_y);
 
 /** Set cursor location.
  *
diff --git a/src/cursor.c b/src/cursor.c
index bd9f04b..5e3f41e 100644
--- a/src/cursor.c
+++ b/src/cursor.c
@@ -36,7 +36,9 @@ bool nsfb_cursor_init(nsfb_t *nsfb)
     return true;
 }
 
-bool nsfb_cursor_set(nsfb_t *nsfb, const nsfb_colour_t *pixel, int bmp_width, int bmp_height, int bmp_stride)
+bool nsfb_cursor_set(nsfb_t *nsfb, const nsfb_colour_t *pixel,
+        int bmp_width, int bmp_height, int bmp_stride,
+        int hotspot_x, int hotspot_y)
 {
     if (nsfb->cursor == NULL) 
         return false;
@@ -47,6 +49,9 @@ bool nsfb_cursor_set(nsfb_t *nsfb, const nsfb_colour_t *pixel, int bmp_width, in
     nsfb->cursor->bmp_stride = bmp_stride;
     nsfb->cursor->loc.x1 = nsfb->cursor->loc.x0 + nsfb->cursor->bmp_width;
     nsfb->cursor->loc.y1 = nsfb->cursor->loc.y0 + nsfb->cursor->bmp_height;
+
+    nsfb->cursor->hotspot_x = hotspot_x;
+    nsfb->cursor->hotspot_y = hotspot_y;
  
     return nsfb->surface_rtns->cursor(nsfb, nsfb->cursor);
 }
@@ -81,6 +86,12 @@ bool nsfb_cursor_plot(nsfb_t *nsfb, struct nsfb_cursor_s *cursor)
     nsfb->plotter_fns->get_clip(nsfb, &sclip);
     nsfb->plotter_fns->set_clip(nsfb, NULL);
 
+    /* offset cursor rect for hotspot */
+    cursor->loc.x0 -= cursor->hotspot_x;
+    cursor->loc.y0 -= cursor->hotspot_y;
+    cursor->loc.x1 -= cursor->hotspot_x;
+    cursor->loc.y1 -= cursor->hotspot_y;
+
     cursor->savloc = cursor->loc;
 
     cursor->sav_width = cursor->savloc.x1 - cursor->savloc.x0;
@@ -91,11 +102,12 @@ bool nsfb_cursor_plot(nsfb_t *nsfb, struct nsfb_cursor_s *cursor)
         cursor->sav = realloc(cursor->sav, sav_size);
         cursor->sav_size = sav_size;
     }
- 
-    nsfb->plotter_fns->readrect(nsfb, &cursor->savloc, cursor->sav );
+
+    nsfb->plotter_fns->readrect(nsfb, &cursor->savloc, cursor->sav);
     cursor->sav_width = cursor->savloc.x1 - cursor->savloc.x0;
     cursor->sav_height = cursor->savloc.y1 - cursor->savloc.y0;
-        
+
+    nsfb->plotter_fns->set_clip(nsfb, NULL);
     nsfb->plotter_fns->bitmap(nsfb, 
                               &cursor->loc,  
                               cursor->pixel, 
@@ -104,6 +116,12 @@ bool nsfb_cursor_plot(nsfb_t *nsfb, struct nsfb_cursor_s *cursor)
                               cursor->bmp_stride, 
                               true);
 
+    /* undo hotspot offset */
+    cursor->loc.x0 += cursor->hotspot_x;
+    cursor->loc.y0 += cursor->hotspot_y;
+    cursor->loc.x1 += cursor->hotspot_x;
+    cursor->loc.y1 += cursor->hotspot_y;
+
     nsfb->plotter_fns->set_clip(nsfb, &sclip);
 
     cursor->plotted = true;
diff --git a/src/surface/sdl.c b/src/surface/sdl.c
index 2a905f5..8908a21 100644
--- a/src/surface/sdl.c
+++ b/src/surface/sdl.c
@@ -636,8 +636,13 @@ sdl_cursor(nsfb_t *nsfb, struct nsfb_cursor_s *cursor)
     nsfb_bbox_t fbarea;
 
     if ((cursor != NULL) && (cursor->plotted == true)) {
+        nsfb_bbox_t loc_shift = cursor->loc;
+        loc_shift.x0 -= cursor->hotspot_x;
+        loc_shift.y0 -= cursor->hotspot_y;
+        loc_shift.x1 -= cursor->hotspot_x;
+        loc_shift.y1 -= cursor->hotspot_y;
 
-        nsfb_plot_add_rect(&cursor->savloc, &cursor->loc, &redraw);
+        nsfb_plot_add_rect(&cursor->savloc, &loc_shift, &redraw);
 
         /* screen area */
         fbarea.x0 = 0;
-- 
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