cc/playback/raster_source_helper.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "cc/playback/raster_source_helper.h"
   6
   7 #include "base/trace_event/trace_event.h"
   8 #include "cc/debug/debug_colors.h"
   9 #include "third_party/skia/include/core/SkCanvas.h"
  10 #include "ui/gfx/geometry/rect_conversions.h"
  11 #include "ui/gfx/skia_util.h"
  12
  13 namespace cc {
  14
  15 void RasterSourceHelper::PrepareForPlaybackToCanvas(
  16     SkCanvas* canvas,
  17     const gfx::Rect& canvas_bitmap_rect,
  18     const gfx::Rect& canvas_playback_rect,
  19     const gfx::Rect& source_rect,
  20     float contents_scale,
  21     SkColor background_color,
  22     bool clear_canvas_with_debug_color,
  23     bool requires_clear) {
  24   bool partial_update = canvas_bitmap_rect != canvas_playback_rect;
  25
  26   if (!partial_update)
  27     canvas->discard();
  28   if (clear_canvas_with_debug_color) {
  29     // Any non-painted areas in the content bounds will be left in this color.
  30     if (!partial_update) {
  31       canvas->clear(DebugColors::NonPaintedFillColor());
  32     } else {
  33       canvas->save();
  34       canvas->clipRect(gfx::RectToSkRect(
  35           canvas_playback_rect - canvas_bitmap_rect.OffsetFromOrigin()));
  36       canvas->drawColor(DebugColors::NonPaintedFillColor());
  37       canvas->restore();
  38     }
  39   }
  40
  41   // If this raster source has opaque contents, it is guaranteeing that it will
  42   // draw an opaque rect the size of the layer.  If it is not, then we must
  43   // clear this canvas ourselves.
  44   if (requires_clear) {
  45     TRACE_EVENT_INSTANT0("cc", "SkCanvas::clear", TRACE_EVENT_SCOPE_THREAD);
  46     // Clearing is about ~4x faster than drawing a rect even if the content
  47     // isn't covering a majority of the canvas.
  48     if (!partial_update) {
  49       canvas->clear(SK_ColorTRANSPARENT);
  50     } else {
  51       canvas->save();
  52       canvas->clipRect(gfx::RectToSkRect(
  53           canvas_playback_rect - canvas_bitmap_rect.OffsetFromOrigin()));
  54       canvas->drawColor(SK_ColorTRANSPARENT, SkXfermode::kClear_Mode);
  55       canvas->restore();
  56     }
  57   } else {
  58     // Even if completely covered, for rasterizations that touch the edge of the
  59     // layer, we also need to raster the background color underneath the last
  60     // texel (since the recording won't cover it) and outside the last texel
  61     // (due to linear filtering when using this texture).
  62     gfx::Rect content_rect =
  63         gfx::ToEnclosingRect(gfx::ScaleRect(source_rect, contents_scale));
  64
  65     // The final texel of content may only be partially covered by a
  66     // rasterization; this rect represents the content rect that is fully
  67     // covered by content.
  68     gfx::Rect deflated_content_rect = content_rect;
  69     deflated_content_rect.Inset(0, 0, 1, 1);
  70     deflated_content_rect.Intersect(canvas_playback_rect);
  71     if (!deflated_content_rect.Contains(canvas_playback_rect)) {
  72       if (clear_canvas_with_debug_color) {
  73         // Any non-painted areas outside of the content bounds are left in
  74         // this color.  If this is seen then it means that cc neglected to
  75         // rerasterize a tile that used to intersect with the content rect
  76         // after the content bounds grew.
  77         canvas->save();
  78         canvas->translate(-canvas_bitmap_rect.x(), -canvas_bitmap_rect.y());
  79         canvas->clipRect(gfx::RectToSkRect(content_rect),
  80                          SkRegion::kDifference_Op);
  81         canvas->drawColor(DebugColors::MissingResizeInvalidations(),
  82                           SkXfermode::kSrc_Mode);
  83         canvas->restore();
  84       }
  85
  86       // Drawing at most 2 x 2 x (canvas width + canvas height) texels is 2-3X
  87       // faster than clearing, so special case this.
  88       canvas->save();
  89       canvas->translate(-canvas_bitmap_rect.x(), -canvas_bitmap_rect.y());
  90       gfx::Rect inflated_content_rect = content_rect;
  91       // Only clear edges that will be inside the canvas_playback_rect, else we
  92       // clear things that are still valid from a previous raster.
  93       inflated_content_rect.Inset(0, 0, -1, -1);
  94       inflated_content_rect.Intersect(canvas_playback_rect);
  95       canvas->clipRect(gfx::RectToSkRect(inflated_content_rect),
  96                        SkRegion::kReplace_Op);
  97       canvas->clipRect(gfx::RectToSkRect(deflated_content_rect),
  98                        SkRegion::kDifference_Op);
  99       canvas->drawColor(background_color, SkXfermode::kSrc_Mode);
 100       canvas->restore();
 101     }
 102   }
 103 }
 104
 105 }  // namespace cc