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         contents_scale_x(1.f),
  31         contents_scale_y(1.f),
  32         num_unclipped_descendants(0),
  33         layer_or_descendant_has_copy_request(false),
  34         layer_or_descendant_has_input_handler(false),
  35         has_child_with_a_scroll_parent(false),
  36         index_of_first_descendants_addition(0),
  37         num_descendants_added(0),
  38         index_of_first_render_surface_layer_list_addition(0),
  39         num_render_surfaces_added(0),
  40         last_drawn_render_surface_layer_list_id(0),
  41         ideal_contents_scale(0.f),
  42         maximum_animation_contents_scale(0.f),
  43         starting_animation_contents_scale(0.f),
  44         page_scale_factor(0.f),
  45         device_scale_factor(0.f) {}
  46
  47   // Transforms objects from content space to target surface space, where
  48   // this layer would be drawn.
  49   gfx::Transform target_space_transform;
  50
  51   // Transforms objects from content space to screen space (viewport space).
  52   gfx::Transform screen_space_transform;
  53
  54   // Known occlusion above the layer mapped to the content space of the layer.
  55   Occlusion occlusion_in_content_space;
  56
  57   // DrawProperties::opacity may be different than LayerType::opacity,
  58   // particularly in the case when a RenderSurface re-parents the layer's
  59   // opacity, or when opacity is compounded by the hierarchy.
  60   float opacity;
  61
  62   // DrawProperties::blend_mode may be different than LayerType::blend_mode,
  63   // when a RenderSurface re-parents the layer's blend_mode.
  64   SkXfermode::Mode blend_mode;
  65
  66   // xxx_is_animating flags are used to indicate whether the DrawProperties
  67   // are actually meaningful on the main thread. When the properties are
  68   // animating, the main thread may not have the same values that are used
  69   // to draw.
  70   bool opacity_is_animating;
  71   bool screen_space_opacity_is_animating;
  72   bool target_space_transform_is_animating;
  73   bool screen_space_transform_is_animating;
  74
  75   // True if the layer can use LCD text.
  76   bool can_use_lcd_text;
  77
  78   // True if the layer needs to be clipped by clip_rect.
  79   bool is_clipped;
  80
  81   // The layer whose coordinate space this layer draws into. This can be
  82   // either the same layer (draw_properties_.render_target == this) or an
  83   // ancestor of this layer.
  84   LayerType* render_target;
  85
  86   // This rect is in the layer's content space.
  87   gfx::Rect visible_content_rect;
  88
  89   // In target surface space, the rect that encloses the clipped, drawable
  90   // content of the layer.
  91   gfx::Rect drawable_content_rect;
  92
  93   // In target surface space, the original rect that clipped this layer. This
  94   // value is used to avoid unnecessarily changing GL scissor state.
  95   gfx::Rect clip_rect;
  96
  97   // The scale used to move between layer space and content space, and bounds
  98   // of the space. One is always a function of the other, but which one
  99   // depends on the layer type. For picture layers, this is an ideal scale,
 100   // and not always the one used.
 101   float contents_scale_x;
 102   float contents_scale_y;
 103   gfx::Size content_bounds;
 104
 105   // Number of descendants with a clip parent that is our ancestor. NB - this
 106   // does not include our clip children because they are clipped by us.
 107   int num_unclipped_descendants;
 108
 109   // If true, the layer or some layer in its sub-tree has a CopyOutputRequest
 110   // present on it.
 111   bool layer_or_descendant_has_copy_request;
 112
 113   // If true, the layer or one of its descendants has a wheel or touch handler.
 114   bool layer_or_descendant_has_input_handler;
 115
 116   // This is true if the layer has any direct child that has a scroll parent.
 117   // This layer will not be the scroll parent in this case. This information
 118   // lets us avoid work in CalculateDrawPropertiesInternal -- if none of our
 119   // children have scroll parents, we will not need to recur out of order.
 120   bool has_child_with_a_scroll_parent;
 121
 122   // If this layer is visited out of order, its contribution to the descendant
 123   // and render surface layer lists will be put aside in a temporary list.
 124   // These values will allow for an efficient reordering of these additions.
 125   size_t index_of_first_descendants_addition;
 126   size_t num_descendants_added;
 127   size_t index_of_first_render_surface_layer_list_addition;
 128   size_t num_render_surfaces_added;
 129
 130   // Each time we generate a new render surface layer list, an ID is used to
 131   // identify it. |last_drawn_render_surface_layer_list_id| is set to the ID
 132   // that marked the render surface layer list generation which last updated
 133   // these draw properties and determined that this layer will draw itself.
 134   // If these draw properties are not a part of the render surface layer list,
 135   // or the layer doesn't contribute anything, then this ID will be either out
 136   // of date or 0.
 137   int last_drawn_render_surface_layer_list_id;
 138
 139   // The scale at which content for the layer should be rastered in order to be
 140   // perfectly crisp.
 141   float ideal_contents_scale;
 142
 143   // The maximum scale during the layers current animation at which content
 144   // should be rastered at to be crisp.
 145   float maximum_animation_contents_scale;
 146
 147   // The scale during the layer animation start at which content should be
 148   // rastered at to be crisp.
 149   float starting_animation_contents_scale;
 150
 151   // The page scale factor that is applied to the layer. Since some layers may
 152   // have page scale applied and others not, this may differ between layers.
 153   float page_scale_factor;
 154
 155   // The device scale factor that is applied to the layer.
 156   float device_scale_factor;
 157 };
 158
 159 }  // namespace cc
 160
 161 #endif  // CC_LAYERS_DRAW_PROPERTIES_H_