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         ideal_contents_scale(0.f),
  40         maximum_animation_contents_scale(0.f),
  41         starting_animation_contents_scale(0.f),
  42         page_scale_factor(0.f),
  43         device_scale_factor(0.f) {}
  44
  45   // Transforms objects from content space to target surface space, where
  46   // this layer would be drawn.
  47   gfx::Transform target_space_transform;
  48
  49   // Transforms objects from content space to screen space (viewport space).
  50   gfx::Transform screen_space_transform;
  51
  52   // Known occlusion above the layer mapped to the content space of the layer.
  53   Occlusion occlusion_in_content_space;
  54
  55   // DrawProperties::opacity may be different than LayerType::opacity,
  56   // particularly in the case when a RenderSurface re-parents the layer's
  57   // opacity, or when opacity is compounded by the hierarchy.
  58   float opacity;
  59
  60   // DrawProperties::blend_mode may be different than LayerType::blend_mode,
  61   // when a RenderSurface re-parents the layer's blend_mode.
  62   SkXfermode::Mode blend_mode;
  63
  64   // xxx_is_animating flags are used to indicate whether the DrawProperties
  65   // are actually meaningful on the main thread. When the properties are
  66   // animating, the main thread may not have the same values that are used
  67   // to draw.
  68   bool opacity_is_animating;
  69   bool screen_space_opacity_is_animating;
  70   bool target_space_transform_is_animating;
  71   bool screen_space_transform_is_animating;
  72
  73   // True if the layer can use LCD text.
  74   bool can_use_lcd_text;
  75
  76   // True if the layer needs to be clipped by clip_rect.
  77   bool is_clipped;
  78
  79   // The layer whose coordinate space this layer draws into. This can be
  80   // either the same layer (draw_properties_.render_target == this) or an
  81   // ancestor of this layer.
  82   LayerType* render_target;
  83
  84   // This rect is a bounding box around what part of the layer is visible, in
  85   // the layer's coordinate space.
  86   gfx::Rect visible_layer_rect;
  87
  88   // In target surface space, the rect that encloses the clipped, drawable
  89   // content of the layer.
  90   gfx::Rect drawable_content_rect;
  91
  92   // In target surface space, the original rect that clipped this layer. This
  93   // value is used to avoid unnecessarily changing GL scissor state.
  94   gfx::Rect clip_rect;
  95
  96   // Number of descendants with a clip parent that is our ancestor. NB - this
  97   // does not include our clip children because they are clipped by us.
  98   size_t num_unclipped_descendants;
  99
 100   // If true, the layer or some layer in its sub-tree has a CopyOutputRequest
 101   // present on it.
 102   bool layer_or_descendant_has_copy_request;
 103
 104   // If true, the layer or one of its descendants has a wheel or touch handler.
 105   bool layer_or_descendant_has_input_handler;
 106
 107   // This is true if the layer has any direct child that has a scroll parent.
 108   // This layer will not be the scroll parent in this case. This information
 109   // lets us avoid work in CalculateDrawPropertiesInternal -- if none of our
 110   // children have scroll parents, we will not need to recur out of order.
 111   bool has_child_with_a_scroll_parent;
 112
 113   // If this layer is visited out of order, its contribution to the descendant
 114   // and render surface layer lists will be put aside in a temporary list.
 115   // These values will allow for an efficient reordering of these additions.
 116   size_t index_of_first_descendants_addition;
 117   size_t num_descendants_added;
 118   size_t index_of_first_render_surface_layer_list_addition;
 119   size_t num_render_surfaces_added;
 120
 121   // Each time we generate a new render surface layer list, an ID is used to
 122   // identify it. |last_drawn_render_surface_layer_list_id| is set to the ID
 123   // that marked the render surface layer list generation which last updated
 124   // these draw properties and determined that this layer will draw itself.
 125   // If these draw properties are not a part of the render surface layer list,
 126   // or the layer doesn't contribute anything, then this ID will be either out
 127   // of date or 0.
 128   int last_drawn_render_surface_layer_list_id;
 129
 130   // The scale at which content for the layer should be rastered in order to be
 131   // perfectly crisp.
 132   float ideal_contents_scale;
 133
 134   // The maximum scale during the layers current animation at which content
 135   // should be rastered at to be crisp.
 136   float maximum_animation_contents_scale;
 137
 138   // The scale during the layer animation start at which content should be
 139   // rastered at to be crisp.
 140   float starting_animation_contents_scale;
 141
 142   // The page scale factor that is applied to the layer. Since some layers may
 143   // have page scale applied and others not, this may differ between layers.
 144   float page_scale_factor;
 145
 146   // The device scale factor that is applied to the layer.
 147   float device_scale_factor;
 148 };
 149
 150 }  // namespace cc
 151
 152 #endif  // CC_LAYERS_DRAW_PROPERTIES_H_