Attachment 277862 Details for Bug 154283 – Patch

[patch] Patch

bug-154283-20160501235937.patch (text/plain), 3.42 KB, created by Gwang Yoon Hwang on 2016-05-01 07:59:02 PDT

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Creator: Gwang Yoon Hwang

Created: 2016-05-01 07:59:02 PDT

Size: 3.42 KB

patch

obsolete

>Subversion Revision: 200303
>diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
>index 1b5d560cefb269e7c63900863abcfbae8b05ea39..e09bbf4491ca803097cf0bb7847d5ea045cc15a4 100644
>--- a/Source/WebCore/ChangeLog
>+++ b/Source/WebCore/ChangeLog
>@@ -1,3 +1,25 @@
>+2016-02-23  Gwang Yoon Hwang  <yoon@igalia.com>
>+
>+        [GTK] scroll with transparent background not repainted after scrollY >= 32768
>+        https://bugs.webkit.org/show_bug.cgi?id=154283
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        If the Cairo's matrix exceeds the limit of Pixman's maximum int size (which is
>+        15bit), Cairo does not render bitmap because the given matrix is invalid.  When
>+        we scroll a page which has a patterned bitmap as a background to more than the
>+        Pixman's maximum int size, it simply doesn't render anything as background and
>+        the target surface ends up with a transparent background.
>+
>+        This patch translates the CTM of Cairo's context when we drawing patterns to
>+        the context to remove invisible area. Because it is a pattern there is no
>+        visual difference between drawing tiles from the visible area and the beginning
>+        of the page. But it is more natural to draw tiles from the visible area for the
>+        performance.
>+
>+        * platform/graphics/cairo/CairoUtilities.cpp:
>+        (WebCore::drawPatternToCairoContext):
>+
> 2016-04-30  Antti Koivisto  <antti@apple.com>
> 
>         REGRESSION (r199640): position:absolute generated content inherits text-decoration from its element
>diff --git a/Source/WebCore/platform/graphics/cairo/CairoUtilities.cpp b/Source/WebCore/platform/graphics/cairo/CairoUtilities.cpp
>index 15e8ffcfb1b239551f7e3d430f10a7cb4afc213a..14ecb12b0f7bcf453efdc5e8a6b4be64d8f112b0 100644
>--- a/Source/WebCore/platform/graphics/cairo/CairoUtilities.cpp
>+++ b/Source/WebCore/platform/graphics/cairo/CairoUtilities.cpp
>@@ -198,6 +198,25 @@ void drawPatternToCairoContext(cairo_t* cr, cairo_surface_t* image, const IntSiz
>         image = clippedImageSurface.get();
>     }
> 
>+    // Cairo cannot convert a cairo_matrix to a Pixman's matrix
>+    // if any of its components is bigger than maximum int size of Pixman.
>+    // With this condition, Cairo gives up to draw given pattern entirely.
>+    // To workaround this problem, we reduce the coordinate space by translating CTM and destRect.
>+    cairo_matrix_t ctm;
>+    cairo_get_matrix(cr, &ctm);
>+
>+    double dx = 0, dy = 0;
>+    cairo_matrix_transform_point(&ctm, &dx, &dy);
>+    double xScale = 1, yScale = 1;
>+    cairo_matrix_transform_distance(&ctm, &xScale, &yScale);
>+
>+    dx = std::floor(-dx / tileRect.width()) * tileRect.width() / xScale;
>+    dy = std::floor(-dy / tileRect.height()) * tileRect.height() / yScale;
>+    cairo_translate(cr, dx, dy);
>+
>+    FloatRect adjustedDestRect(destRect);
>+    adjustedDestRect.move(-dx, -dy);
>+
>     cairo_pattern_t* pattern = cairo_pattern_create_for_surface(image);
>     cairo_pattern_set_extend(pattern, CAIRO_EXTEND_REPEAT);
> 
>@@ -211,7 +230,7 @@ void drawPatternToCairoContext(cairo_t* cr, cairo_surface_t* image, const IntSiz
>     cairo_set_operator(cr, op);
>     cairo_set_source(cr, pattern);
>     cairo_pattern_destroy(pattern);
>-    cairo_rectangle(cr, destRect.x(), destRect.y(), destRect.width(), destRect.height());
>+    cairo_rectangle(cr, adjustedDestRect.x(), adjustedDestRect.y(), adjustedDestRect.width(), adjustedDestRect.height());
>     cairo_fill(cr);
> 
>     cairo_restore(cr);

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