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