cc/layers/draw_properties.h

   1 // Copyright 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 CC_LAYERS_DRAW_PROPERTIES_H_
   6 #define CC_LAYERS_DRAW_PROPERTIES_H_
   7
   8 #include "base/memory/scoped_ptr.h"
   9 #include "cc/trees/occlusion.h"
  10 #include "third_party/skia/include/core/SkXfermode.h"
  11 #include "ui/gfx/geometry/rect.h"
  12 #include "ui/gfx/transform.h"
  13
  14 namespace cc {
  15
  16 // Container for properties that layers need to compute before they can be
  17 // drawn.
  18 template <typename LayerType>
  19 struct CC_EXPORT DrawProperties {
  20   DrawProperties()
  21       : opacity(0.f),
  22         screen_space_transform_is_animating(false),
  23         can_use_lcd_text(false),
  24         render_target(nullptr),
  25         num_unclipped_descendants(0),
  26         layer_or_descendant_has_copy_request(false),
  27         layer_or_descendant_has_input_handler(false),
  28         has_child_with_a_scroll_parent(false),
  29         last_drawn_render_surface_layer_list_id(0),
  30         maximum_animation_contents_scale(0.f),
  31         starting_animation_contents_scale(0.f) {}
  32
  33   // Transforms objects from content space to target surface space, where
  34   // this layer would be drawn.
  35   gfx::Transform target_space_transform;
  36
  37   // Transforms objects from content space to screen space (viewport space).
  38   gfx::Transform screen_space_transform;
  39
  40   // Known occlusion above the layer mapped to the content space of the layer.
  41   Occlusion occlusion_in_content_space;
  42
  43   // DrawProperties::opacity may be different than LayerType::opacity,
  44   // particularly in the case when a RenderSurface re-parents the layer's
  45   // opacity, or when opacity is compounded by the hierarchy.
  46   float opacity;
  47
  48   // xxx_is_animating flags are used to indicate whether the DrawProperties
  49   // are actually meaningful on the main thread. When the properties are
  50   // animating, the main thread may not have the same values that are used
  51   // to draw.
  52   bool screen_space_transform_is_animating;
  53
  54   // True if the layer can use LCD text.
  55   bool can_use_lcd_text;
  56
  57   // The layer whose coordinate space this layer draws into. This can be
  58   // either the same layer (draw_properties_.render_target == this) or an
  59   // ancestor of this layer.
  60   LayerType* render_target;
  61
  62   // This rect is a bounding box around what part of the layer is visible, in
  63   // the layer's coordinate space.
  64   gfx::Rect visible_layer_rect;
  65
  66   // In target surface space, the rect that encloses the clipped, drawable
  67   // content of the layer.
  68   gfx::Rect drawable_content_rect;
  69
  70   // In target surface space, the original rect that clipped this layer. This
  71   // value is used to avoid unnecessarily changing GL scissor state.
  72   gfx::Rect clip_rect;
  73
  74   // Number of descendants with a clip parent that is our ancestor. NB - this
  75   // does not include our clip children because they are clipped by us.
  76   size_t num_unclipped_descendants;
  77
  78   // If true, the layer or some layer in its sub-tree has a CopyOutputRequest
  79   // present on it.
  80   bool layer_or_descendant_has_copy_request;
  81
  82   // If true, the layer or one of its descendants has a wheel or touch handler.
  83   bool layer_or_descendant_has_input_handler;
  84
  85   // This is true if the layer has any direct child that has a scroll parent.
  86   // This layer will not be the scroll parent in this case. This information
  87   // lets us avoid work in CalculateDrawPropertiesInternal -- if none of our
  88   // children have scroll parents, we will not need to recur out of order.
  89   bool has_child_with_a_scroll_parent;
  90
  91   // Each time we generate a new render surface layer list, an ID is used to
  92   // identify it. |last_drawn_render_surface_layer_list_id| is set to the ID
  93   // that marked the render surface layer list generation which last updated
  94   // these draw properties and determined that this layer will draw itself.
  95   // If these draw properties are not a part of the render surface layer list,
  96   // or the layer doesn't contribute anything, then this ID will be either out
  97   // of date or 0.
  98   int last_drawn_render_surface_layer_list_id;
  99
 100   // The maximum scale during the layers current animation at which content
 101   // should be rastered at to be crisp.
 102   float maximum_animation_contents_scale;
 103
 104   // The scale during the layer animation start at which content should be
 105   // rastered at to be crisp.
 106   float starting_animation_contents_scale;
 107 };
 108
 109 }  // namespace cc
 110
 111 #endif  // CC_LAYERS_DRAW_PROPERTIES_H_