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         sorted_for_recursion(false),
  37         visited(false),
  38         index_of_first_descendants_addition(0),
  39         num_descendants_added(0),
  40         index_of_first_render_surface_layer_list_addition(0),
  41         num_render_surfaces_added(0),
  42         last_drawn_render_surface_layer_list_id(0),
  43         ideal_contents_scale(0.f),
  44         maximum_animation_contents_scale(0.f),
  45         page_scale_factor(0.f),
  46         device_scale_factor(0.f) {}
  47
  48   // Transforms objects from content space to target surface space, where
  49   // this layer would be drawn.
  50   gfx::Transform target_space_transform;
  51
  52   // Transforms objects from content space to screen space (viewport space).
  53   gfx::Transform screen_space_transform;
  54
  55   // Known occlusion above the layer mapped to the content space of the layer.
  56   Occlusion occlusion_in_content_space;
  57
  58   // DrawProperties::opacity may be different than LayerType::opacity,
  59   // particularly in the case when a RenderSurface re-parents the layer's
  60   // opacity, or when opacity is compounded by the hierarchy.
  61   float opacity;
  62
  63   // DrawProperties::blend_mode may be different than LayerType::blend_mode,
  64   // when a RenderSurface re-parents the layer's blend_mode.
  65   SkXfermode::Mode blend_mode;
  66
  67   // xxx_is_animating flags are used to indicate whether the DrawProperties
  68   // are actually meaningful on the main thread. When the properties are
  69   // animating, the main thread may not have the same values that are used
  70   // to draw.
  71   bool opacity_is_animating;
  72   bool screen_space_opacity_is_animating;
  73   bool target_space_transform_is_animating;
  74   bool screen_space_transform_is_animating;
  75
  76   // True if the layer can use LCD text.
  77   bool can_use_lcd_text;
  78
  79   // True if the layer needs to be clipped by clip_rect.
  80   bool is_clipped;
  81
  82   // The layer whose coordinate space this layer draws into. This can be
  83   // either the same layer (draw_properties_.render_target == this) or an
  84   // ancestor of this layer.
  85   LayerType* render_target;
  86
  87   // This rect is in the layer's content space.
  88   gfx::Rect visible_content_rect;
  89
  90   // In target surface space, the rect that encloses the clipped, drawable
  91   // content of the layer.
  92   gfx::Rect drawable_content_rect;
  93
  94   // In target surface space, the original rect that clipped this layer. This
  95   // value is used to avoid unnecessarily changing GL scissor state.
  96   gfx::Rect clip_rect;
  97
  98   // The scale used to move between layer space and content space, and bounds
  99   // of the space. One is always a function of the other, but which one
 100   // depends on the layer type. For picture layers, this is an ideal scale,
 101   // and not always the one used.
 102   float contents_scale_x;
 103   float contents_scale_y;
 104   gfx::Size content_bounds;
 105
 106   // Number of descendants with a clip parent that is our ancestor. NB - this
 107   // does not include our clip children because they are clipped by us.
 108   int num_unclipped_descendants;
 109
 110   // If true, the layer or some layer in its sub-tree has a CopyOutputRequest
 111   // present on it.
 112   bool layer_or_descendant_has_copy_request;
 113
 114   // If true, the layer or one of its descendants has a wheel or touch handler.
 115   bool layer_or_descendant_has_input_handler;
 116
 117   // This is true if the layer has any direct child that has a scroll parent.
 118   // This layer will not be the scroll parent in this case. This information
 119   // lets us avoid work in CalculateDrawPropertiesInternal -- if none of our
 120   // children have scroll parents, we will not need to recur out of order.
 121   bool has_child_with_a_scroll_parent;
 122
 123   // This is true if the order (wrt to its siblings in the tree) in which the
 124   // layer will be visited while computing draw properties has been determined.
 125   bool sorted_for_recursion;
 126
 127   // This is used to sanity-check CDP and ensure that we don't revisit a layer.
 128   bool visited;
 129
 130   // If this layer is visited out of order, its contribution to the descendant
 131   // and render surface layer lists will be put aside in a temporary list.
 132   // These values will allow for an efficient reordering of these additions.
 133   size_t index_of_first_descendants_addition;
 134   size_t num_descendants_added;
 135   size_t index_of_first_render_surface_layer_list_addition;
 136   size_t num_render_surfaces_added;
 137
 138   // Each time we generate a new render surface layer list, an ID is used to
 139   // identify it. |last_drawn_render_surface_layer_list_id| is set to the ID
 140   // that marked the render surface layer list generation which last updated
 141   // these draw properties and determined that this layer will draw itself.
 142   // If these draw properties are not a part of the render surface layer list,
 143   // or the layer doesn't contribute anything, then this ID will be either out
 144   // of date or 0.
 145   int last_drawn_render_surface_layer_list_id;
 146
 147   // The scale at which content for the layer should be rastered in order to be
 148   // perfectly crisp.
 149   float ideal_contents_scale;
 150
 151   // The maximum scale during the layers current animation at which content
 152   // should be rastered at to be crisp.
 153   float maximum_animation_contents_scale;
 154
 155   // The page scale factor that is applied to the layer. Since some layers may
 156   // have page scale applied and others not, this may differ between layers.
 157   float page_scale_factor;
 158
 159   // The device scale factor that is applied to the layer.
 160   float device_scale_factor;
 161 };
 162
 163 }  // namespace cc
 164
 165 #endif  // CC_LAYERS_DRAW_PROPERTIES_H_