ui/app_list/views/cached_label.cc

   1 // Copyright 2013 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 "ui/app_list/views/cached_label.h"
   6
   7 #include "base/strings/utf_string_conversions.h"
   8 #include "ui/base/layout.h"
   9 #include "ui/gfx/canvas.h"
  10 #include "ui/views/widget/widget.h"
  11
  12 namespace app_list {
  13
  14 CachedLabel::CachedLabel()
  15     : needs_repaint_(true) {
  16 }
  17
  18 void CachedLabel::PaintToBackingImage() {
  19   if (image_.size() == size() && !needs_repaint_)
  20     return;
  21
  22   bool is_opaque = SkColorGetA(background_color()) == 0xFF;
  23   float scale_factor =
  24       ui::GetScaleFactorForNativeView(GetWidget()->GetNativeView());
  25   gfx::Canvas canvas(size(), scale_factor, is_opaque);
  26   // If a background is provided, it will initialize the canvas in
  27   // View::OnPaintBackground(). Otherwise, the background must be set here.
  28   if (!background()) {
  29     canvas.FillRect(
  30         GetLocalBounds(), background_color(), SkXfermode::kSrc_Mode);
  31   }
  32   Label::OnPaint(&canvas);
  33   image_ = gfx::ImageSkia(canvas.ExtractImageRep());
  34   needs_repaint_ = false;
  35 }
  36
  37 #if defined(OS_WIN)
  38 void CachedLabel::OnPaint(gfx::Canvas* canvas) {
  39   PaintToBackingImage();
  40   canvas->DrawImageInt(image_, 0, 0);
  41 }
  42 #endif
  43
  44 void CachedLabel::OnDeviceScaleFactorChanged(
  45     float device_scale_factor) {
  46   Invalidate();
  47   View::OnDeviceScaleFactorChanged(device_scale_factor);
  48 }
  49
  50 }  // namespace app_list