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 "ui/gfx/rect.h"
  10 #include "ui/gfx/transform.h"
  11
  12 namespace cc {
  13
  14 // Container for properties that layers need to compute before they can be
  15 // drawn.
  16 template <typename LayerType>
  17 struct CC_EXPORT DrawProperties {
  18   DrawProperties()
  19       : opacity(0.f),
  20         opacity_is_animating(false),
  21         screen_space_opacity_is_animating(false),
  22         target_space_transform_is_animating(false),
  23         screen_space_transform_is_animating(false),
  24         can_use_lcd_text(false),
  25         is_clipped(false),
  26         render_target(NULL),
  27         contents_scale_x(1.f),
  28         contents_scale_y(1.f),
  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         sorted_for_recursion(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         page_scale_factor(0.f),
  42         device_scale_factor(0.f) {}
  43
  44   // Transforms objects from content space to target surface space, where
  45   // this layer would be drawn.
  46   gfx::Transform target_space_transform;
  47
  48   // Transforms objects from content space to screen space (viewport space).
  49   gfx::Transform screen_space_transform;
  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   // xxx_is_animating flags are used to indicate whether the DrawProperties
  57   // are actually meaningful on the main thread. When the properties are
  58   // animating, the main thread may not have the same values that are used
  59   // to draw.
  60   bool opacity_is_animating;
  61   bool screen_space_opacity_is_animating;
  62   bool target_space_transform_is_animating;
  63   bool screen_space_transform_is_animating;
  64
  65   // True if the layer can use LCD text.
  66   bool can_use_lcd_text;
  67
  68   // True if the layer needs to be clipped by clip_rect.
  69   bool is_clipped;
  70
  71   // The layer whose coordinate space this layer draws into. This can be
  72   // either the same layer (draw_properties_.render_target == this) or an
  73   // ancestor of this layer.
  74   LayerType* render_target;
  75
  76   // The surface that this layer and its subtree would contribute to.
  77   scoped_ptr<typename LayerType::RenderSurfaceType> render_surface;
  78
  79   // This rect is in the layer's content space.
  80   gfx::Rect visible_content_rect;
  81
  82   // In target surface space, the rect that encloses the clipped, drawable
  83   // content of the layer.
  84   gfx::Rect drawable_content_rect;
  85
  86   // In target surface space, the original rect that clipped this layer. This
  87   // value is used to avoid unnecessarily changing GL scissor state.
  88   gfx::Rect clip_rect;
  89
  90   // The scale used to move between layer space and content space, and bounds
  91   // of the space. One is always a function of the other, but which one
  92   // depends on the layer type. For picture layers, this is an ideal scale,
  93   // and not always the one used.
  94   float contents_scale_x;
  95   float contents_scale_y;
  96   gfx::Size content_bounds;
  97
  98   // Number of descendants with a clip parent that is our ancestor. NB - this
  99   // does not include our clip children because they are clipped by us.
 100   int num_unclipped_descendants;
 101
 102   // If true, the layer or some layer in its sub-tree has a CopyOutputRequest
 103   // present on it.
 104   bool layer_or_descendant_has_copy_request;
 105
 106   // If true, the layer or one of its descendants has a wheel or touch handler.
 107   bool layer_or_descendant_has_input_handler;
 108
 109   // This is true if the layer has any direct child that has a scroll parent.
 110   // This layer will not be the scroll parent in this case. This information
 111   // lets us avoid work in CalculateDrawPropertiesInternal -- if none of our
 112   // children have scroll parents, we will not need to recur out of order.
 113   bool has_child_with_a_scroll_parent;
 114
 115   // This is true if the order (wrt to its siblings in the tree) in which the
 116   // layer will be visited while computing draw properties has been determined.
 117   bool sorted_for_recursion;
 118
 119   // If this layer is visited out of order, its contribution to the descendant
 120   // and render surface layer lists will be put aside in a temporary list.
 121   // These values will allow for an efficient reordering of these additions.
 122   size_t index_of_first_descendants_addition;
 123   size_t num_descendants_added;
 124   size_t index_of_first_render_surface_layer_list_addition;
 125   size_t num_render_surfaces_added;
 126
 127   // Each time we generate a new render surface layer list, an ID is used to
 128   // identify it. |last_drawn_render_surface_layer_list_id| is set to the ID
 129   // that marked the render surface layer list generation which last updated
 130   // these draw properties and determined that this layer will draw itself.
 131   // If these draw properties are not a part of the render surface layer list,
 132   // or the layer doesn't contribute anything, then this ID will be either out
 133   // of date or 0.
 134   int last_drawn_render_surface_layer_list_id;
 135
 136   // The scale at which content for the layer should be rastered in order to be
 137   // perfectly crisp.
 138   float ideal_contents_scale;
 139
 140   // The maximum scale during the layers current animation at which content
 141   // should be rastered at to be crisp.
 142   float maximum_animation_contents_scale;
 143
 144   // The page scale factor that is applied to the layer. Since some layers may
 145   // have page scale applied and others not, this may differ between layers.
 146   float page_scale_factor;
 147
 148   // The device scale factor that is applied to the layer.
 149   float device_scale_factor;
 150 };
 151
 152 }  // namespace cc
 153
 154 #endif  // CC_LAYERS_DRAW_PROPERTIES_H_