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, 9 insertions, 9 deletions

diff --git a/source/html/epub-doc.c b/source/html/epub-doc.c
index deb45f92..5325c316 100644
--- a/source/html/epub-doc.c
+++ b/source/html/epub-doc.c
@@ -121,31 +121,31 @@ epub_drop_page(fz_context *ctx, fz_page *page_)
 {
 }
 
-static fz_rect *
-epub_bound_page(fz_context *ctx, fz_page *page_, fz_rect *bbox)
+static fz_rect
+epub_bound_page(fz_context *ctx, fz_page *page_)
 {
 	epub_page *page = (epub_page*)page_;
 	epub_document *doc = page->doc;
 	epub_chapter *ch;
 	int n = page->number;
 	int count = 0;
+	fz_rect bbox;
 
 	for (ch = doc->spine; ch; ch = ch->next)
 	{
 		int cn = count_chapter_pages(ch);
 		if (n < count + cn)
 		{
-			bbox->x0 = 0;
-			bbox->y0 = 0;
-			bbox->x1 = ch->html->page_w + ch->html->page_margin[L] + ch->html->page_margin[R];
-			bbox->y1 = ch->html->page_h + ch->html->page_margin[T] + ch->html->page_margin[B];
+			bbox.x0 = 0;
+			bbox.y0 = 0;
+			bbox.x1 = ch->html->page_w + ch->html->page_margin[L] + ch->html->page_margin[R];
+			bbox.y1 = ch->html->page_h + ch->html->page_margin[T] + ch->html->page_margin[B];
 			return bbox;
 		}
 		count += cn;
 	}
 
-	*bbox = fz_unit_rect;
-	return bbox;
+	return fz_unit_rect;
 }
 
 static void
@@ -162,7 +162,7 @@ epub_run_page(fz_context *ctx, fz_page *page_, fz_device *dev, const fz_matrix *
 		int cn = count_chapter_pages(ch);
 		if (n < count + cn)
 		{
-			fz_draw_html(ctx, dev, ctm, ch->html, n-count);
+			fz_draw_html(ctx, dev, *ctm, ch->html, n-count);
 			break;
 		}
 		count += cn;