src/ui/wm/core/image_grid.h

   1 // Copyright (c) 2012 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 #ifndef UI_WM_CORE_IMAGE_GRID_H_
   6 #define UI_WM_CORE_IMAGE_GRID_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/gtest_prod_util.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "ui/compositor/layer.h"
  12 #include "ui/compositor/layer_delegate.h"
  13 #include "ui/gfx/image/image_skia.h"
  14 #include "ui/gfx/rect.h"
  15 #include "ui/gfx/size.h"
  16 #include "ui/wm/wm_export.h"
  17
  18 namespace gfx {
  19 class Image;
  20 }  // namespace gfx
  21
  22 namespace wm {
  23
  24 // An ImageGrid is a 3x3 array of ui::Layers, each containing an image.
  25 //
  26 // As the grid is resized, its images fill the requested space:
  27 // - corner images are not scaled
  28 // - top and bottom images are scaled horizontally
  29 // - left and right images are scaled vertically
  30 // - the center image is scaled in both directions
  31 //
  32 // If one of the non-center images is smaller than the largest images in its
  33 // row or column, it will be aligned with the outside of the grid.  For
  34 // example, given 4x4 top-left and top-right images and a 1x2 top images:
  35 //
  36 //   +--------+---------------------+--------+
  37 //   |        |         top         |        |
  38 //   | top-   +---------------------+  top-  +
  39 //   | left   |                     | right  |
  40 //   +----+---+                     +---+----+
  41 //   |    |                             |    |
  42 //   ...
  43 //
  44 // This may seem odd at first, but it lets ImageGrid be used to draw shadows
  45 // with curved corners that extend inwards beyond a window's borders.  In the
  46 // below example, the top-left corner image is overlaid on top of the window's
  47 // top-left corner:
  48 //
  49 //   +---------+-----------------------
  50 //   |    ..xxx|XXXXXXXXXXXXXXXXXX
  51 //   |  .xXXXXX|XXXXXXXXXXXXXXXXXX_____
  52 //   | .xXX    |                    ^ window's top edge
  53 //   | .xXX    |
  54 //   +---------+
  55 //   | xXX|
  56 //   | xXX|< window's left edge
  57 //   | xXX|
  58 //   ...
  59 //
  60 class WM_EXPORT ImageGrid {
  61  public:
  62   // Helper class for use by tests.
  63   class WM_EXPORT TestAPI {
  64    public:
  65     TestAPI(ImageGrid* grid) : grid_(grid) {}
  66
  67     gfx::Rect top_left_clip_rect() const {
  68       return grid_->top_left_painter_->clip_rect_;
  69     }
  70     gfx::Rect top_right_clip_rect() const {
  71       return grid_->top_right_painter_->clip_rect_;
  72     }
  73     gfx::Rect bottom_left_clip_rect() const {
  74       return grid_->bottom_left_painter_->clip_rect_;
  75     }
  76     gfx::Rect bottom_right_clip_rect() const {
  77       return grid_->bottom_right_painter_->clip_rect_;
  78     }
  79
  80     // Returns |layer|'s bounds after applying the layer's current transform.
  81     gfx::RectF GetTransformedLayerBounds(const ui::Layer& layer);
  82
  83    private:
  84     ImageGrid* grid_;  // not owned
  85
  86     DISALLOW_COPY_AND_ASSIGN(TestAPI);
  87   };
  88
  89   ImageGrid();
  90   ~ImageGrid();
  91
  92   ui::Layer* layer() { return layer_.get(); }
  93   int top_image_height() const { return top_image_height_; }
  94   int bottom_image_height() const { return bottom_image_height_; }
  95   int left_image_width() const { return left_image_width_; }
  96   int right_image_width() const { return right_image_width_; }
  97
  98   // Visible to allow independent layer animations and for testing.
  99   ui::Layer* top_left_layer() const { return top_left_layer_.get(); }
 100   ui::Layer* top_layer() const { return top_layer_.get(); }
 101   ui::Layer* top_right_layer() const { return top_right_layer_.get(); }
 102   ui::Layer* left_layer() const { return left_layer_.get(); }
 103   ui::Layer* center_layer() const { return center_layer_.get(); }
 104   ui::Layer* right_layer() const { return right_layer_.get(); }
 105   ui::Layer* bottom_left_layer() const { return bottom_left_layer_.get(); }
 106   ui::Layer* bottom_layer() const { return bottom_layer_.get(); }
 107   ui::Layer* bottom_right_layer() const { return bottom_right_layer_.get(); }
 108
 109   // Sets the grid to display the passed-in images (any of which can be NULL).
 110   // Ownership of the images remains with the caller.  May be called more than
 111   // once to switch images.
 112   void SetImages(const gfx::Image* top_left_image,
 113                  const gfx::Image* top_image,
 114                  const gfx::Image* top_right_image,
 115                  const gfx::Image* left_image,
 116                  const gfx::Image* center_image,
 117                  const gfx::Image* right_image,
 118                  const gfx::Image* bottom_left_image,
 119                  const gfx::Image* bottom_image,
 120                  const gfx::Image* bottom_right_image);
 121
 122   void SetSize(const gfx::Size& size);
 123
 124   // Sets the grid to a position and size such that the inner edges of the top,
 125   // bottom, left and right images will be flush with |content_bounds_in_dip|.
 126   void SetContentBounds(const gfx::Rect& content_bounds_in_dip);
 127
 128  private:
 129   // Delegate responsible for painting a specific image on a layer.
 130   class ImagePainter : public ui::LayerDelegate {
 131    public:
 132     ImagePainter(const gfx::ImageSkia& image) : image_(image) {}
 133     ~ImagePainter() override {}
 134
 135     // Clips |layer| to |clip_rect|.  Triggers a repaint if the clipping
 136     // rectangle has changed.  An empty rectangle disables clipping.
 137     void SetClipRect(const gfx::Rect& clip_rect, ui::Layer* layer);
 138
 139     // ui::LayerDelegate implementation:
 140     void OnPaintLayer(gfx::Canvas* canvas) override;
 141     void OnDelegatedFrameDamage(const gfx::Rect& damage_rect_in_dip) override;
 142     void OnDeviceScaleFactorChanged(float device_scale_factor) override;
 143     base::Closure PrepareForLayerBoundsChange() override;
 144
 145    private:
 146     friend class TestAPI;
 147
 148     const gfx::ImageSkia image_;
 149
 150     gfx::Rect clip_rect_;
 151
 152     DISALLOW_COPY_AND_ASSIGN(ImagePainter);
 153   };
 154
 155   enum ImageType {
 156     HORIZONTAL,
 157     VERTICAL,
 158     NONE,
 159   };
 160
 161   // Sets |layer_ptr| and |painter_ptr| to display |image| and adds the
 162   // passed-in layer to |layer_|.  If image is NULL resets |layer_ptr| and
 163   // |painter_ptr| and removes any existing layer from |layer_|.
 164   // If |type| is either HORIZONTAL or VERTICAL, it may resize the image to
 165   // guarantee that it has minimum size in order for scaling work properly
 166   // with fractional device scale factors. crbug.com/376519.
 167   void SetImage(const gfx::Image* image,
 168                 scoped_ptr<ui::Layer>* layer_ptr,
 169                 scoped_ptr<ImagePainter>* painter_ptr,
 170                 ImageType type);
 171
 172   // Layer that contains all of the image layers.
 173   scoped_ptr<ui::Layer> layer_;
 174
 175   // The grid's dimensions.
 176   gfx::Size size_;
 177
 178   // Heights and widths of the images displayed by |top_layer_|,
 179   // |bottom_layer_|, |left_layer_|, and |right_layer_|.
 180   int top_image_height_;
 181   int bottom_image_height_;
 182   int left_image_width_;
 183   int right_image_width_;
 184
 185   // Heights of the tallest images in the top and bottom rows and the widest
 186   // images in the left and right columns.  Note that we may have less actual
 187   // space than this available if the images are large and |size_| is small.
 188   int base_top_row_height_;
 189   int base_bottom_row_height_;
 190   int base_left_column_width_;
 191   int base_right_column_width_;
 192
 193   // Layers used to display the various images.  Children of |layer_|.
 194   // Positions for which no images were supplied are NULL.
 195   scoped_ptr<ui::Layer> top_left_layer_;
 196   scoped_ptr<ui::Layer> top_layer_;
 197   scoped_ptr<ui::Layer> top_right_layer_;
 198   scoped_ptr<ui::Layer> left_layer_;
 199   scoped_ptr<ui::Layer> center_layer_;
 200   scoped_ptr<ui::Layer> right_layer_;
 201   scoped_ptr<ui::Layer> bottom_left_layer_;
 202   scoped_ptr<ui::Layer> bottom_layer_;
 203   scoped_ptr<ui::Layer> bottom_right_layer_;
 204
 205   // Delegates responsible for painting the above layers.
 206   // Positions for which no images were supplied are NULL.
 207   scoped_ptr<ImagePainter> top_left_painter_;
 208   scoped_ptr<ImagePainter> top_painter_;
 209   scoped_ptr<ImagePainter> top_right_painter_;
 210   scoped_ptr<ImagePainter> left_painter_;
 211   scoped_ptr<ImagePainter> center_painter_;
 212   scoped_ptr<ImagePainter> right_painter_;
 213   scoped_ptr<ImagePainter> bottom_left_painter_;
 214   scoped_ptr<ImagePainter> bottom_painter_;
 215   scoped_ptr<ImagePainter> bottom_right_painter_;
 216
 217   DISALLOW_COPY_AND_ASSIGN(ImageGrid);
 218 };
 219
 220 }  // namespace wm
 221
 222 #endif  // UI_WM_CORE_IMAGE_GRID_H_