Pass rect and matrix by value in geometry functions.

Several things irk me about passing values as const pointers:

* They can be NULL, which is not a valid value.
* They require explicit temporary variables for storage.
* They don't compose easily in a legible manner, requiring
  weird pointer passing semantics where the variable being assigned
  is hidden as an argument in the innermost function call.
* We can't change the value through the pointer, requiring yet more
  local variables to hold copies of the input value.

In the device interface where we pass a matrix to a function, we often
find ourselves making a local copy of the matrix so we can concatenate
other transforms to it. This copying is a lot of unnecessary busywork
that I hope to eventually avoid by laying the groundwork with this
commit.

This is a rather large API change, so I apologize for the inconvenience,
but I hope the end result and gain in legibility will be worth the pain.

1 files changed, 27 insertions, 28 deletions

diff --git a/source/fitz/svg-device.c b/source/fitz/svg-device.c
index c5905938..28f3a4d6 100644
--- a/source/fitz/svg-device.c
+++ b/source/fitz/svg-device.c
@@ -173,7 +173,7 @@ svg_dev_stroke_state(fz_context *ctx, svg_device *sdev, const fz_stroke_state *s
 	fz_output *out = sdev->out;
 	float exp;
 
-	exp = fz_matrix_expansion(ctm);
+	exp = fz_matrix_expansion(*ctm);
 	if (exp == 0)
 		exp = 1;
 	exp = stroke_state->linewidth/exp;
@@ -269,13 +269,13 @@ find_first_char(fz_context *ctx, const fz_text_span *span, int i)
 }
 
 static int
-find_next_line_break(fz_context *ctx, const fz_text_span *span, const fz_matrix *inv_tm, int i)
+find_next_line_break(fz_context *ctx, const fz_text_span *span, fz_matrix inv_tm, int i)
 {
 	fz_point p, old_p;
 
 	old_p.x = span->items[i].x;
 	old_p.y = span->items[i].y;
-	fz_transform_point(&old_p, inv_tm);
+	old_p = fz_transform_point(old_p, inv_tm);
 
 	for (++i; i < span->len; ++i)
 	{
@@ -283,7 +283,7 @@ find_next_line_break(fz_context *ctx, const fz_text_span *span, const fz_matrix
 		{
 			p.x = span->items[i].x;
 			p.y = span->items[i].y;
-			fz_transform_point(&p, inv_tm);
+			p = fz_transform_point(p, inv_tm);
 			if (span->wmode == 0)
 			{
 				if (p.y != old_p.y)
@@ -332,15 +332,15 @@ svg_dev_text_span(fz_context *ctx, svg_device *sdev, const fz_matrix *ctm, const
 	}
 
 	tm = span->trm;
-	font_size = fz_matrix_expansion(&tm);
+	font_size = fz_matrix_expansion(tm);
 	final_tm.a = tm.a / font_size;
 	final_tm.b = tm.b / font_size;
 	final_tm.c = -tm.c / font_size;
 	final_tm.d = -tm.d / font_size;
 	final_tm.e = 0;
 	final_tm.f = 0;
-	fz_invert_matrix(&inv_tm, &final_tm);
-	fz_concat(&final_tm, &final_tm, ctm);
+	inv_tm = fz_invert_matrix(final_tm);
+	final_tm = fz_concat(final_tm, *ctm);
 
 	tm.e = span->items[0].x;
 	tm.f = span->items[0].y;
@@ -362,11 +362,11 @@ svg_dev_text_span(fz_context *ctx, svg_device *sdev, const fz_matrix *ctm, const
 	start = find_first_char(ctx, span, 0);
 	while (start < span->len)
 	{
-		end = find_next_line_break(ctx, span, &inv_tm, start);
+		end = find_next_line_break(ctx, span, inv_tm, start);
 
 		p.x = span->items[start].x;
 		p.y = span->items[start].y;
-		fz_transform_point(&p, &inv_tm);
+		p = fz_transform_point(p, inv_tm);
 		if (span->items[start].gid >= 0)
 			cluster_advance = svg_cluster_advance(ctx, span, start, end);
 		if (span->wmode == 0)
@@ -384,7 +384,7 @@ svg_dev_text_span(fz_context *ctx, svg_device *sdev, const fz_matrix *ctm, const
 				{
 					p.x = it->x;
 					p.y = it->y;
-					fz_transform_point(&p, &inv_tm);
+					p = fz_transform_point(p, inv_tm);
 				}
 				else
 				{
@@ -476,10 +476,10 @@ svg_dev_text_span_as_paths_defs(fz_context *ctx, fz_device *dev, fz_text_span *s
 			path = fz_outline_glyph(ctx, span->font, gid, &fz_identity);
 			if (path)
 			{
-				fz_bound_path(ctx, path, NULL, &fz_identity, &rect);
+				rect = fz_bound_path(ctx, path, NULL, fz_identity);
 				shift.e = -rect.x0;
 				shift.f = -rect.y0;
-				fz_transform_path(ctx, path, &shift);
+				fz_transform_path(ctx, path, shift);
 				out = start_def(ctx, sdev);
 				fz_write_printf(ctx, out, "<symbol id=\"font_%x_%x\">\n", fnt->id, gid);
 				fz_write_printf(ctx, out, "<path");
@@ -489,7 +489,7 @@ svg_dev_text_span_as_paths_defs(fz_context *ctx, fz_device *dev, fz_text_span *s
 			}
 			else
 			{
-				fz_bound_glyph(ctx, span->font, gid, &fz_identity, &rect);
+				rect = fz_bound_glyph(ctx, span->font, gid, fz_identity);
 				shift.e = -rect.x0;
 				shift.f = -rect.y0;
 				out = start_def(ctx, sdev);
@@ -536,8 +536,8 @@ svg_dev_text_span_as_paths_fill(fz_context *ctx, fz_device *dev, const fz_text_s
 		shift.f = fnt->sentlist[gid].y_off;
 		local_trm.e = it->x;
 		local_trm.f = it->y;
-		fz_concat(&local_trm2, &local_trm, ctm);
-		fz_concat(&local_trm2, &shift, &local_trm2);
+		local_trm2 = fz_concat(local_trm, *ctm);
+		local_trm2 = fz_concat(shift, local_trm2);
 		fz_write_printf(ctx, out, "<use xlink:href=\"#font_%x_%x\"", fnt->id, gid);
 		svg_dev_ctm(ctx, sdev, &local_trm2);
 		svg_dev_fill_color(ctx, sdev, colorspace, color, alpha, color_params);
@@ -576,8 +576,8 @@ svg_dev_text_span_as_paths_stroke(fz_context *ctx, fz_device *dev, const fz_text
 		shift.f = fnt->sentlist[gid].y_off;
 		local_trm.e = it->x;
 		local_trm.f = it->y;
-		fz_concat(&local_trm2, &local_trm, ctm);
-		fz_concat(&local_trm2, &shift, &local_trm2);
+		local_trm2 = fz_concat(local_trm, *ctm);
+		local_trm2 = fz_concat(shift, local_trm2);
 		fz_write_printf(ctx, out, "<use xlink:href=\"#font_%x_%x\"", fnt->id, gid);
 		svg_dev_stroke_state(ctx, sdev, stroke, &local_trm2);
 		svg_dev_ctm(ctx, sdev, &local_trm2);
@@ -649,7 +649,7 @@ svg_dev_clip_stroke_path(fz_context *ctx, fz_device *dev, const fz_path *path, c
 	int num = sdev->id++;
 	float white[3] = { 1, 1, 1 };
 
-	fz_bound_path(ctx, path, stroke, ctm, &bounds);
+	bounds = fz_bound_path(ctx, path, stroke, *ctm);
 
 	out = start_def(ctx, sdev);
 	fz_write_printf(ctx, out, "<mask id=\"ma%d\" x=\"%g\" y=\"%g\" width=\"%g\" height=\"%g\" maskUnits=\"userSpaceOnUse\" maskContentUnits=\"userSpaceOnUse\">\n",
@@ -732,7 +732,7 @@ svg_dev_clip_text(fz_context *ctx, fz_device *dev, const fz_text *text, const fz
 	font *fnt;
 	fz_text_span *span;
 
-	fz_bound_text(ctx, text, NULL, ctm, &bounds);
+	bounds = fz_bound_text(ctx, text, NULL, *ctm);
 
 	out = start_def(ctx, sdev);
 	fz_write_printf(ctx, out, "<mask id=\"ma%d\" x=\"%g\" y=\"%g\" width=\"%g\" height=\"%g\"",
@@ -772,7 +772,7 @@ svg_dev_clip_stroke_text(fz_context *ctx, fz_device *dev, const fz_text *text, c
 	font *fnt;
 	fz_text_span *span;
 
-	fz_bound_text(ctx, text, NULL, ctm, &bounds);
+	bounds = fz_bound_text(ctx, text, NULL, *ctm);
 
 	out = start_def(ctx, sdev);
 	fz_write_printf(ctx, out, "<mask id=\"ma%d\" x=\"%g\" y=\"%g\" width=\"%g\" height=\"%g\"",
@@ -890,7 +890,7 @@ svg_dev_fill_image(fz_context *ctx, fz_device *dev, fz_image *image, const fz_ma
 	scale.a = 1.0f / image->w;
 	scale.d = 1.0f / image->h;
 
-	fz_concat(&local_ctm, &scale, ctm);
+	local_ctm = fz_concat(scale, *ctm);
 	fz_write_printf(ctx, out, "<g");
 	if (alpha != 1.0f)
 		fz_write_printf(ctx, out, " opacity=\"%g\"", alpha);
@@ -905,7 +905,6 @@ svg_dev_fill_shade(fz_context *ctx, fz_device *dev, fz_shade *shade, const fz_ma
 {
 	svg_device *sdev = (svg_device*)dev;
 	fz_output *out = sdev->out;
-	fz_rect rect;
 	fz_irect bbox;
 	fz_pixmap *pix;
 	fz_buffer *buf = NULL;
@@ -915,10 +914,10 @@ svg_dev_fill_shade(fz_context *ctx, fz_device *dev, fz_shade *shade, const fz_ma
 	if (dev->container_len == 0)
 		return;
 
-	fz_round_rect(&bbox, fz_intersect_rect(fz_bound_shade(ctx, shade, ctm, &rect), &dev->container[dev->container_len-1].scissor));
-	if (fz_is_empty_irect(&bbox))
+	bbox = fz_round_rect(fz_intersect_rect(fz_bound_shade(ctx, shade, *ctm), dev->container[dev->container_len-1].scissor));
+	if (fz_is_empty_irect(bbox))
 		return;
-	pix = fz_new_pixmap_with_bbox(ctx, fz_device_rgb(ctx), &bbox, NULL, 1);
+	pix = fz_new_pixmap_with_bbox(ctx, fz_device_rgb(ctx), bbox, NULL, 1);
 	fz_clear_pixmap(ctx, pix);
 
 	fz_try(ctx)
@@ -957,7 +956,7 @@ svg_dev_fill_image_mask(fz_context *ctx, fz_device *dev, fz_image *image, const
 	scale.a = 1.0f / image->w;
 	scale.d = 1.0f / image->h;
 
-	fz_concat(&local_ctm, &scale, ctm);
+	local_ctm = fz_concat(scale, *ctm);
 	out = start_def(ctx, sdev);
 	fz_write_printf(ctx, out, "<mask id=\"ma%d\">\n", mask);
 	svg_send_image(ctx, sdev, image, color_params);
@@ -981,7 +980,7 @@ svg_dev_clip_image_mask(fz_context *ctx, fz_device *dev, fz_image *image, const
 	scale.a = 1.0f / image->w;
 	scale.d = 1.0f / image->h;
 
-	fz_concat(&local_ctm, &scale, ctm);
+	local_ctm = fz_concat(scale, *ctm);
 	out = start_def(ctx, sdev);
 	fz_write_printf(ctx, out, "<mask id=\"ma%d\">\n<g", mask);
 	svg_dev_ctm(ctx, sdev, &local_ctm);
@@ -1139,7 +1138,7 @@ svg_dev_end_tile(fz_context *ctx, fz_device *dev)
 
 	/* All the pattern contents will have their own ctm applied. Let's
 	 * undo the current one to allow for this */
-	fz_invert_matrix(&inverse, &t->ctm);
+	inverse = fz_invert_matrix(t->ctm);
 	fz_write_printf(ctx, out, "<g");
 	svg_dev_ctm(ctx, sdev, &inverse);
 	fz_write_printf(ctx, out, ">\n");