Modified: releases/WebKitGTK/webkit-2.14/Source/WebCore/ChangeLog (212081 => 212082)
--- releases/WebKitGTK/webkit-2.14/Source/WebCore/ChangeLog 2017-02-10 07:53:14 UTC (rev 212081)
+++ releases/WebKitGTK/webkit-2.14/Source/WebCore/ChangeLog 2017-02-10 07:57:04 UTC (rev 212082)
@@ -1,3 +1,28 @@
+2017-02-09 Miguel Gomez <mago...@igalia.com>
+
+ [GTK] scroll with transparent background not repainted after scrollY >= 32768
+ https://bugs.webkit.org/show_bug.cgi?id=154283
+
+ Reviewed by Carlos Garcia Campos.
+
+ Due to a limitation of the pixman backend, which uses 16 bits to hold signed integers, cairo is
+ not able to draw anything when using transformation matrices with values bigger than 32768. When
+ drawing patterns into large pages, the matrices values can overflow those 16 bits, so cairo doesn't
+ draw anything in, which causes the reported transparent backgrounds.
+
+ The patch modifies the transformation matrices both from the current context and the pattern we
+ are painting, to avoid them to hold values that cannot stored in 16 bits.
+
+ There's still the possibility that this happens, but it would require using a pattern with a size
+ bigger than 32768.
+
+ Based on a previous patch by Gwang Yoon Hwang <y...@igalia.com>.
+
+ No new tests.
+
+ * platform/graphics/cairo/CairoUtilities.cpp:
+ (WebCore::drawPatternToCairoContext):
+
2017-02-08 Miguel Gomez <mago...@igalia.com>
[GTK] Reduce TiledBackingStore tile coverage when on memory pressure state
Modified: releases/WebKitGTK/webkit-2.14/Source/WebCore/platform/graphics/cairo/CairoUtilities.cpp (212081 => 212082)
--- releases/WebKitGTK/webkit-2.14/Source/WebCore/platform/graphics/cairo/CairoUtilities.cpp 2017-02-10 07:53:14 UTC (rev 212081)
+++ releases/WebKitGTK/webkit-2.14/Source/WebCore/platform/graphics/cairo/CairoUtilities.cpp 2017-02-10 07:57:04 UTC (rev 212082)
@@ -201,8 +201,28 @@
cairo_pattern_t* pattern = cairo_pattern_create_for_surface(image);
cairo_pattern_set_extend(pattern, CAIRO_EXTEND_REPEAT);
+ // 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::trunc(-dx / tileRect.width()) * tileRect.width() / xScale;
+ dy = std::trunc(-dy / tileRect.height()) * tileRect.height() / yScale;
+ cairo_translate(cr, dx, dy);
+
+ FloatRect adjustedDestRect(destRect);
+ adjustedDestRect.move(-dx, -dy);
+
+ // Again, we need to reduce the coordinate of the transformation matrix we are using for the pattern.
cairo_matrix_t patternMatrix = cairo_matrix_t(patternTransform);
- cairo_matrix_t phaseMatrix = {1, 0, 0, 1, phase.x() + tileRect.x() * patternTransform.a(), phase.y() + tileRect.y() * patternTransform.d()};
+ dx = phase.x() - std::trunc(phase.x() / tileRect.width()) * tileRect.width();
+ dy = phase.y() - std::trunc(phase.y() / tileRect.height()) * tileRect.height();
+ cairo_matrix_t phaseMatrix = {1, 0, 0, 1, dx + tileRect.x() * patternTransform.a(), dy + tileRect.y() * patternTransform.d()};
cairo_matrix_t combined;
cairo_matrix_multiply(&combined, &patternMatrix, &phaseMatrix);
cairo_matrix_invert(&combined);
@@ -211,7 +231,7 @@
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);
