Selection: Remove client callback for unit conversion.

Now clients provide a unit conversion context and libcss provides
code to perform unit conversion.

This reduces the amount of common code that clients have to write.

5 files changed, 76 insertions, 179 deletions

diff --git a/src/select/computed.c b/src/select/computed.c
index a1b345b..d075af9 100644
--- a/src/select/computed.c
+++ b/src/select/computed.c
@@ -12,6 +12,7 @@
 #include "select/dispatch.h"
 #include "select/propget.h"
 #include "select/propset.h"
+#include "select/unit.h"
 #include "utils/utils.h"
 
 static css_error compute_absolute_color(css_computed_style *style,
@@ -247,9 +248,7 @@ css_error css__computed_style_initialise(css_computed_style *style,
 css_error css_computed_style_compose(
 		const css_computed_style *restrict parent,
 		const css_computed_style *restrict child,
-		css_error (*compute_font_size)(void *pw,
-			const css_hint *parent, css_hint *size),
-		void *pw,
+		const css_unit_len_ctx *unit_len_ctx,
 		css_computed_style **restrict result)
 {
 	css_computed_style *composed;
@@ -275,8 +274,7 @@ css_error css_computed_style_compose(
 	}
 
 	/* Finally, compute absolute values for everything */
-	error = css__compute_absolute_values(parent, composed,
-			compute_font_size, pw);
+	error = css__compute_absolute_values(parent, composed, unit_len_ctx);
 	if (error != CSS_OK) {
 		return error;
 	}
@@ -1087,31 +1085,36 @@ uint8_t css_computed_order(const css_computed_style *style,
  *
  * \param parent             Parent style, or NULL for tree root
  * \param style              Computed style to process
- * \param compute_font_size  Callback to calculate an absolute font-size
- * \param pw                 Private word for callback
+ * \param unit_len_ctx       Client length conversion context.
  * \return CSS_OK on success.
  */
 css_error css__compute_absolute_values(const css_computed_style *parent,
 		css_computed_style *style,
-		css_error (*compute_font_size)(void *pw,
-			const css_hint *parent, css_hint *size),
-		void *pw)
+		const css_unit_len_ctx *unit_len_ctx)
 {
+	css_hint_length *ref_length = NULL;
 	css_hint psize, size, ex_size;
 	css_error error;
 
-	/* Ensure font-size is absolute */
+	/* Get reference font-size for relative sizes. */
 	if (parent != NULL) {
 		psize.status = get_font_size(parent,
 				&psize.data.length.value,
 				&psize.data.length.unit);
+		if (psize.status != CSS_FONT_SIZE_DIMENSION) {
+			return CSS_BADPARM;
+		}
+		ref_length = &psize.data.length;
 	}
 
 	size.status = get_font_size(style,
 			&size.data.length.value,
 			&size.data.length.unit);
 
-	error = compute_font_size(pw, parent != NULL ? &psize : NULL, &size);
+	error = css_unit_compute_absolute_font_size(ref_length,
+			unit_len_ctx->root_style,
+			unit_len_ctx->font_size_default,
+			&size);
 	if (error != CSS_OK)
 		return error;
 
@@ -1125,7 +1128,12 @@ css_error css__compute_absolute_values(const css_computed_style *parent,
 	ex_size.status = CSS_FONT_SIZE_DIMENSION;
 	ex_size.data.length.value = INTTOFIX(1);
 	ex_size.data.length.unit = CSS_UNIT_EX;
-	error = compute_font_size(pw, &size, &ex_size);
+
+	error = css_unit_compute_absolute_font_size(
+			&size.data.length,
+			unit_len_ctx->root_style,
+			unit_len_ctx->font_size_default,
+			&ex_size);
 	if (error != CSS_OK)
 		return error;
 
diff --git a/src/select/computed.h b/src/select/computed.h
index c926cec..8b33405 100644
--- a/src/select/computed.h
+++ b/src/select/computed.h
@@ -10,6 +10,8 @@
 
 #include <libcss/computed.h>
 #include <libcss/hint.h>
+#include <libcss/unit.h>
+
 #include "autogenerated_computed.h"
 
 /**
@@ -35,8 +37,6 @@ css_error css__computed_style_initialise(css_computed_style *style,
 
 css_error css__compute_absolute_values(const css_computed_style *parent,
 		css_computed_style *style,
-		css_error (*compute_font_size)(void *pw,
-			const css_hint *parent, css_hint *size),
-		void *pw);
+		const css_unit_len_ctx *unit_len_ctx);
 
 #endif
diff --git a/src/select/select.c b/src/select/select.c
index f6efbfe..03a45fe 100644
--- a/src/select/select.c
+++ b/src/select/select.c
@@ -23,6 +23,7 @@
 #include "select/propset.h"
 #include "select/font_face.h"
 #include "select/select.h"
+#include "select/unit.h"
 #include "utils/parserutilserror.h"
 #include "utils/utils.h"
 
@@ -1164,6 +1165,7 @@ failed:
  *
  * \param ctx             Selection context to use
  * \param node            Node to select style for
+ * \param unit_len_ctx    Context for length unit conversions.
  * \param media           Currently active media specification
  * \param inline_style    Corresponding inline style for node, or NULL
  * \param handler         Dispatch table of handler functions
@@ -1181,6 +1183,7 @@ failed:
  * update the fully computed style for a node when layout changes.
  */
 css_error css_select_style(css_select_ctx *ctx, void *node,
+		const css_unit_len_ctx *unit_len_ctx,
 		const css_media *media, const css_stylesheet *inline_style,
 		css_select_handler *handler, void *pw,
 		css_select_results **result)
@@ -1353,7 +1356,7 @@ css_error css_select_style(css_select_ctx *ctx, void *node,
 		/* Only compute absolute values for the base element */
 		error = css__compute_absolute_values(NULL,
 				state.results->styles[CSS_PSEUDO_ELEMENT_NONE],
-				handler->compute_font_size, pw);
+				unit_len_ctx);
 		if (error != CSS_OK)
 			goto cleanup;
 	}
diff --git a/src/select/unit.c b/src/select/unit.c
index f9ecf83..a279ec7 100644
--- a/src/select/unit.c
+++ b/src/select/unit.c
@@ -115,14 +115,15 @@ static inline css_fixed css_unit__absolute_len2pt(
 	}
 }
 
-/* Exported function, documented in unit.h. */
+/* Exported function, documented in libcss/unit.h. */
 css_fixed css_unit_font_size_len2pt(
+		const css_computed_style *style,
 		const css_unit_len_ctx *ctx,
 		const css_fixed length,
 		const css_unit unit)
 {
 	return css_unit__absolute_len2pt(
-			ctx->ref_style,
+			style,
 			ctx->viewport_height,
 			ctx->viewport_width,
 			length,
@@ -303,15 +304,16 @@ css_fixed css_unit_len2px_mq(
 	return FMUL(length, TRUNCATEFIX(px_per_unit));
 }
 
-/* Exported function, documented in unit.h. */
+/* Exported function, documented in libcss/unit.h. */
 css_fixed css_unit_len2css_px(
+		const css_computed_style *style,
 		const css_unit_len_ctx *ctx,
 		const css_fixed length,
 		const css_unit unit)
 {
 	css_fixed px_per_unit = css_unit__px_per_unit(
 			ctx->measure,
-			ctx->ref_style,
+			style,
 			ctx->root_style,
 			ctx->font_size_default,
 			ctx->font_size_minimum,
@@ -328,15 +330,16 @@ css_fixed css_unit_len2css_px(
 	return FMUL(length, TRUNCATEFIX(px_per_unit));
 }
 
-/* Exported function, documented in unit.h. */
+/* Exported function, documented in libcss/unit.h. */
 css_fixed css_unit_len2device_px(
+		const css_computed_style *style,
 		const css_unit_len_ctx *ctx,
 		const css_fixed length,
 		const css_unit unit)
 {
 	css_fixed px_per_unit = css_unit__px_per_unit(
 			ctx->measure,
-			ctx->ref_style,
+			style,
 			ctx->root_style,
 			ctx->font_size_default,
 			ctx->font_size_minimum,
@@ -361,18 +364,18 @@ css_fixed css_unit_len2device_px(
  * The computed style will have font-size with an absolute unit.
  * If no computed style is given, the client default font-size will be returned.
  *
- * \param[in]  ctx    Length unit conversion context.
- * \param[in]  style  The style to get the font-size for, or NULL.
+ * \param[in] style              Reference style.  (Element or parent, or NULL).
+ * \param[in] font_size_default  Client default font size in CSS pixels.
  * \return The font size in absolute units.
  */
 static inline css_hint_length css_unit__get_font_size(
-		const css_unit_len_ctx *ctx,
-		const css_computed_style *style)
+		const css_computed_style *style,
+		css_fixed font_size_default)
 {
 	css_hint_length size;
 
 	if (style == NULL) {
-		size.value = ctx->font_size_default;
+		size.value = font_size_default;
 		size.unit = CSS_UNIT_PX;
 	} else {
 		enum css_font_size_e status = get_font_size(
@@ -391,10 +394,24 @@ static inline css_hint_length css_unit__get_font_size(
 
 /* Exported function, documented in unit.h. */
 css_error css_unit_compute_absolute_font_size(
-		const css_unit_len_ctx *ctx,
+		const css_hint_length *ref_length,
+		const css_computed_style *root_style,
+		css_fixed font_size_default,
 		css_hint *size)
 {
-	css_hint_length ref_len;
+	css_hint_length ref_len = {
+		.value = font_size_default,
+		.unit = CSS_UNIT_PX,
+	};
+
+	if (ref_length != NULL) {
+		/* Must be absolute. */
+		assert(ref_length->unit != CSS_UNIT_EM);
+		assert(ref_length->unit != CSS_UNIT_EX);
+		assert(ref_length->unit != CSS_UNIT_PCT);
+
+		ref_len = *ref_length;
+	}
 
 	assert(size->status != CSS_FONT_SIZE_INHERIT);
 
@@ -420,20 +437,18 @@ css_error css_unit_compute_absolute_font_size(
 		assert(CSS_FONT_SIZE_XX_SMALL == 1);
 
 		size->data.length.value = FMUL(factors[size->status - 1],
-				ctx->font_size_default);
+				font_size_default);
 		size->data.length.unit = CSS_UNIT_PX;
 		size->status = CSS_FONT_SIZE_DIMENSION;
 		break;
 	}
 	case CSS_FONT_SIZE_LARGER:
-		ref_len = css_unit__get_font_size(ctx, ctx->ref_style);
 		size->data.length.value = FMUL(ref_len.value, FLTTOFIX(1.2));
 		size->data.length.unit = ref_len.unit;
 		size->status = CSS_FONT_SIZE_DIMENSION;
 		break;
 
 	case CSS_FONT_SIZE_SMALLER:
-		ref_len = css_unit__get_font_size(ctx, ctx->ref_style);
 		size->data.length.value = FDIV(ref_len.value, FLTTOFIX(1.2));
 		size->data.length.unit = ref_len.unit;
 		size->status = CSS_FONT_SIZE_DIMENSION;
@@ -443,9 +458,8 @@ css_error css_unit_compute_absolute_font_size(
 		/* Convert any relative units to absolute. */
 		switch (size->data.length.unit) {
 		case CSS_UNIT_PCT:
-			ref_len = css_unit__get_font_size(ctx, ctx->ref_style);
-			size->data.length.value = FDIV(
-					FMUL(size->data.length.value,
+			size->data.length.value = FDIV(FMUL(
+					size->data.length.value,
 					ref_len.value), INTTOFIX(100));
 			size->data.length.unit = ref_len.unit;
 			break;
@@ -454,11 +468,8 @@ css_error css_unit_compute_absolute_font_size(
 		case CSS_UNIT_EX: /* Fall-through */
 		case CSS_UNIT_CH:
 			/* Parent relative units. */
-			ref_len = css_unit__get_font_size(ctx, ctx->ref_style);
-
-			size->data.length.unit = ref_len.unit;
-			size->data.length.value = FMUL(size->data.length.value,
-						ref_len.value);
+			size->data.length.value = FMUL(
+					size->data.length.value, ref_len.value);
 
 			switch (size->data.length.unit) {
 			case CSS_UNIT_EX:
@@ -476,15 +487,17 @@ css_error css_unit_compute_absolute_font_size(
 			default:
 				break;
 			}
+			size->data.length.unit = ref_len.unit;
 			break;
 
 		case CSS_UNIT_REM:
 			/* Root element relative units. */
-			ref_len = css_unit__get_font_size(ctx, ctx->root_style);
+			ref_len = css_unit__get_font_size(root_style,
+					font_size_default);
 
 			size->data.length.unit = ref_len.unit;
-			size->data.length.value = FMUL(size->data.length.value,
-						ref_len.value);
+			size->data.length.value = FMUL(
+					size->data.length.value, ref_len.value);
 			break;
 
 		default:
diff --git a/src/select/unit.h b/src/select/unit.h
index 738c181..e4d21da 100644
--- a/src/select/unit.h
+++ b/src/select/unit.h
@@ -9,138 +9,7 @@
 #ifndef css_select_unit_h_
 #define css_select_unit_h_
 
-/**
- * Client callback for font measuring.
- *
- * \param[in]  pw     Client data.
- * \param[in]  style  Style to measure font for, or NULL.
- * \param[in]  unit   Either CSS_UNIT_EX, or CSS_UNIT_CH.
- * \return length in CSS pixels.
- */
-typedef css_fixed (*css_unit_len_measure)(
-		void *pw,
-		const css_computed_style *style,
-		const css_unit unit);
-
-/**
- * LibCSS unit conversion context.
- *
- * The client callback is optional.  It is used for measuring "ch"
- * (glyph '0' advance) and "ex" (height of the letter 'x') units.
- * If a NULL pointer is given, LibCSS will use a fixed scaling of
- * the "em" unit.
- */
-typedef struct css_unit_len_ctx {
-	/**
-	 * Viewport width in CSS pixels.
-	 * Used if unit is vh, vw, vi, vb, vmin, or vmax.
-	 */
-	css_fixed viewport_width;
-	/**
-	 * Viewport height in CSS pixels.
-	 * Used if unit is vh, vw, vi, vb, vmin, or vmax.
-	 */
-	css_fixed viewport_height;
-	/**
-	 * Client default font size in CSS pixels.
-	 */
-	css_fixed font_size_default;
-	/**
-	 * Client minimum font size in CSS pixels.  May be zero.
-	 */
-	css_fixed font_size_minimum;
-	/**
-	 * DPI of the device the style is selected for.
-	 */
-	css_fixed device_dpi;
-	/**
-	 * Reference style.  Most of the time, this is the element's style.
-	 * When converting a length for a typographical property, such as
-	 * font-size, then this should be the parent node.  If the node has
-	 * no parent then this may be NULL.
-	 */
-	const css_computed_style *ref_style;
-	/**
-	 * Computed style for the document root element.
-	 * May be NULL if unit is not rem.
-	 */
-	const css_computed_style *root_style;
-	/**
-	 * Client private word for measure callback.
-	 */
-	void *pw;
-	/**
-	 * Client callback for font measuring.
-	 */
-	const css_unit_len_measure measure;
-} css_unit_len_ctx;
-
-/**
- * Convert css pixels to physical pixels.
- *
- * \param[in] css_pixels  Length in css pixels.
- * \param[in] device_dpi  Device dots per inch.
- * \return Length in device pixels.
- */
-static inline css_fixed css_unit_css2device_px(
-		const css_fixed css_pixels,
-		const css_fixed device_dpi)
-{
-	return FDIV(FMUL(css_pixels, device_dpi), F_96);
-}
-
-/**
- * Convert device pixels to css pixels.
- *
- * \param[in] device_pixels  Length in physical pixels.
- * \param[in] device_dpi     Device dots per inch.
- * \return Length in css pixels.
- */
-static inline css_fixed css_unit_device2css_px(
-		const css_fixed device_pixels,
-		const css_fixed device_dpi)
-{
-	return FDIV(FMUL(device_pixels, F_96), device_dpi);
-}
-
-/**
- * Convert a length to points (pt).
- *
- * \param[in]  ctx     Length unit conversion context.
- * \param[in]  length  Length to convert.
- * \param[in]  unit    Current unit of length.
- * \return A length in points.
- */
-css_fixed css_unit_font_size_len2pt(
-		const css_unit_len_ctx *ctx,
-		const css_fixed length,
-		const css_unit unit);
-
-/**
- * Convert a length to CSS pixels.
- *
- * \param[in]  ctx     Length unit conversion context.
- * \param[in]  length  Length to convert.
- * \param[in]  unit    Current unit of length.
- * \return A length in CSS pixels.
- */
-css_fixed css_unit_len2css_px(
-		const css_unit_len_ctx *ctx,
-		const css_fixed length,
-		const css_unit unit);
-
-/**
- * Convert a length to device pixels.
- *
- * \param[in]  ctx     Length unit conversion context.
- * \param[in]  length  Length to convert.
- * \param[in]  unit    Current unit of length.
- * \return A length in device pixels.
- */
-css_fixed css_unit_len2device_px(
-		const css_unit_len_ctx *ctx,
-		const css_fixed length,
-		const css_unit unit);
+#include <libcss/unit.h>
 
 /**
  * Convert a length to CSS pixels for a media query context.
@@ -158,12 +27,16 @@ css_fixed css_unit_len2px_mq(
 /**
  * Convert relative font size units to absolute units.
  *
- * \param[in]     ctx   Length unit conversion context.
- * \param[in,out] size  The length to convert.
+ * \param[in] ref_length         Reference font-size length or NULL.
+ * \param[in] root_style         Root element style or NULL.
+ * \param[in] font_size_default  Client default font size in CSS pixels.
+ * \param[in,out] size           The length to convert.
  * \return CSS_OK on success, or appropriate error otherwise.
  */
 css_error css_unit_compute_absolute_font_size(
-		const css_unit_len_ctx *ctx,
+		const css_hint_length *ref_length,
+		const css_computed_style *root_style,
+		css_fixed font_size_default,
 		css_hint *size);
 
 #endif