cc/tile_priority.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_TILE_PRIORITY_H_
   6 #define CC_TILE_PRIORITY_H_
   7
   8 #include "base/memory/ref_counted.h"
   9 #include "cc/picture_pile.h"
  10 #include "ui/gfx/rect.h"
  11 #include "ui/gfx/size.h"
  12
  13 namespace cc {
  14
  15 enum WhichTree {
  16   // Note: these must be 0 and 1 because we index with them in various places,
  17   // e.g. in Tile::priority_.
  18   ACTIVE_TREE = 0,
  19   PENDING_TREE = 1
  20 };
  21
  22 enum TileResolution {
  23   LOW_RESOLUTION = 0 ,
  24   HIGH_RESOLUTION = 1,
  25   NON_IDEAL_RESOLUTION = 2
  26 };
  27
  28 struct TilePriority {
  29   TilePriority()
  30      : resolution(NON_IDEAL_RESOLUTION),
  31        time_to_visible_in_seconds(std::numeric_limits<float>::max()),
  32        time_to_ideal_resolution_in_seconds(std::numeric_limits<float>::max()),
  33        distance_to_visible_in_pixels(std::numeric_limits<float>::max()) {}
  34
  35   TilePriority(const TilePriority& active, const TilePriority& pending) {
  36     if (active.resolution == HIGH_RESOLUTION ||
  37         pending.resolution == HIGH_RESOLUTION)
  38       resolution = HIGH_RESOLUTION;
  39     else if (active.resolution == LOW_RESOLUTION ||
  40              pending.resolution == LOW_RESOLUTION)
  41       resolution = LOW_RESOLUTION;
  42     else
  43       resolution = NON_IDEAL_RESOLUTION;
  44
  45     time_to_visible_in_seconds =
  46       std::min(active.time_to_visible_in_seconds,
  47                pending.time_to_visible_in_seconds);
  48     time_to_ideal_resolution_in_seconds =
  49       std::min(active.time_to_ideal_resolution_in_seconds,
  50                pending.time_to_ideal_resolution_in_seconds);
  51     distance_to_visible_in_pixels =
  52       std::min(active.distance_to_visible_in_pixels,
  53                pending.distance_to_visible_in_pixels);
  54   }
  55
  56   float time_to_needed_in_seconds() const {
  57     return std::min(time_to_visible_in_seconds,
  58                     time_to_ideal_resolution_in_seconds);
  59   }
  60
  61   TileResolution resolution;
  62   float time_to_visible_in_seconds;
  63   float time_to_ideal_resolution_in_seconds;
  64   float distance_to_visible_in_pixels;
  65 };
  66
  67 enum TileMemoryLimitPolicy {
  68   // Nothing.
  69   ALLOW_NOTHING,
  70
  71   // You might be made visible, but you're not being interacted with.
  72   ALLOW_ABSOLUTE_MINIMUM, // Tall.
  73
  74   // You're being interacted with, but we're low on memory.
  75   ALLOW_PREPAINT_ONLY, // Grande.
  76
  77   // You're the only thing in town. Go crazy.
  78   ALLOW_ANYTHING, // Venti.
  79 };
  80
  81 class GlobalStateThatImpactsTilePriority {
  82  public:
  83   GlobalStateThatImpactsTilePriority()
  84     : memory_limit_policy(ALLOW_NOTHING)
  85     , memory_limit_in_bytes(0)
  86     , smoothness_takes_priority(false) {
  87   }
  88
  89   TileMemoryLimitPolicy memory_limit_policy;
  90
  91   size_t memory_limit_in_bytes;
  92
  93   // Set when scrolling.
  94   bool smoothness_takes_priority;
  95 };
  96
  97 }  // namespace cc
  98
  99 #endif  // CC_TILE_PRIORITY_H_