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         blend_mode(SkXfermode::kSrcOver_Mode),
  23         opacity_is_animating(false),
  24         screen_space_opacity_is_animating(false),
  25         target_space_transform_is_animating(false),
  26         screen_space_transform_is_animating(false),
  27         can_use_lcd_text(false),
  28         is_clipped(false),
  29         render_target(nullptr),
  30         num_unclipped_descendants(0),
  31         layer_or_descendant_has_copy_request(false),
  32         layer_or_descendant_has_input_handler(false),
  33         has_child_with_a_scroll_parent(false),
  34         index_of_first_descendants_addition(0),
  35         num_descendants_added(0),
  36         index_of_first_render_surface_layer_list_addition(0),
  37         num_render_surfaces_added(0),
  38         last_drawn_render_surface_layer_list_id(0),
  39         maximum_animation_contents_scale(0.f),
  40         starting_animation_contents_scale(0.f) {}
  41
  42   // Transforms objects from content space to target surface space, where
  43   // this layer would be drawn.
  44   gfx::Transform target_space_transform;
  45
  46   // Transforms objects from content space to screen space (viewport space).
  47   gfx::Transform screen_space_transform;
  48
  49   // Known occlusion above the layer mapped to the content space of the layer.
  50   Occlusion occlusion_in_content_space;
  51
  52   // DrawProperties::opacity may be different than LayerType::opacity,
  53   // particularly in the case when a RenderSurface re-parents the layer's
  54   // opacity, or when opacity is compounded by the hierarchy.
  55   float opacity;
  56
  57   // DrawProperties::blend_mode may be different than LayerType::blend_mode,
  58   // when a RenderSurface re-parents the layer's blend_mode.
  59   SkXfermode::Mode blend_mode;
  60
  61   // xxx_is_animating flags are used to indicate whether the DrawProperties
  62   // are actually meaningful on the main thread. When the properties are
  63   // animating, the main thread may not have the same values that are used
  64   // to draw.
  65   bool opacity_is_animating;
  66   bool screen_space_opacity_is_animating;
  67   bool target_space_transform_is_animating;
  68   bool screen_space_transform_is_animating;
  69
  70   // True if the layer can use LCD text.
  71   bool can_use_lcd_text;
  72
  73   // True if the layer needs to be clipped by clip_rect.
  74   bool is_clipped;
  75
  76   // The layer whose coordinate space this layer draws into. This can be
  77   // either the same layer (draw_properties_.render_target == this) or an
  78   // ancestor of this layer.
  79   LayerType* render_target;
  80
  81   // This rect is a bounding box around what part of the layer is visible, in
  82   // the layer's coordinate space.
  83   gfx::Rect visible_layer_rect;
  84
  85   // In target surface space, the rect that encloses the clipped, drawable
  86   // content of the layer.
  87   gfx::Rect drawable_content_rect;
  88
  89   // In target surface space, the original rect that clipped this layer. This
  90   // value is used to avoid unnecessarily changing GL scissor state.
  91   gfx::Rect clip_rect;
  92
  93   // Number of descendants with a clip parent that is our ancestor. NB - this
  94   // does not include our clip children because they are clipped by us.
  95   size_t num_unclipped_descendants;
  96
  97   // If true, the layer or some layer in its sub-tree has a CopyOutputRequest
  98   // present on it.
  99   bool layer_or_descendant_has_copy_request;
 100
 101   // If true, the layer or one of its descendants has a wheel or touch handler.
 102   bool layer_or_descendant_has_input_handler;
 103
 104   // This is true if the layer has any direct child that has a scroll parent.
 105   // This layer will not be the scroll parent in this case. This information
 106   // lets us avoid work in CalculateDrawPropertiesInternal -- if none of our
 107   // children have scroll parents, we will not need to recur out of order.
 108   bool has_child_with_a_scroll_parent;
 109
 110   // If this layer is visited out of order, its contribution to the descendant
 111   // and render surface layer lists will be put aside in a temporary list.
 112   // These values will allow for an efficient reordering of these additions.
 113   size_t index_of_first_descendants_addition;
 114   size_t num_descendants_added;
 115   size_t index_of_first_render_surface_layer_list_addition;
 116   size_t num_render_surfaces_added;
 117
 118   // Each time we generate a new render surface layer list, an ID is used to
 119   // identify it. |last_drawn_render_surface_layer_list_id| is set to the ID
 120   // that marked the render surface layer list generation which last updated
 121   // these draw properties and determined that this layer will draw itself.
 122   // If these draw properties are not a part of the render surface layer list,
 123   // or the layer doesn't contribute anything, then this ID will be either out
 124   // of date or 0.
 125   int last_drawn_render_surface_layer_list_id;
 126
 127   // The maximum scale during the layers current animation at which content
 128   // should be rastered at to be crisp.
 129   float maximum_animation_contents_scale;
 130
 131   // The scale during the layer animation start at which content should be
 132   // rastered at to be crisp.
 133   float starting_animation_contents_scale;
 134 };
 135
 136 }  // namespace cc
 137
 138 #endif  // CC_LAYERS_DRAW_PROPERTIES_H_