/**
* Expands a given rectangle to the next tile boundary. Note, this will
* expand the rectangle if it is already on tile boundaries.
*/
static CSSRect ExpandDisplayPortToTileBoundaries(
const CSSRect& aDisplayPort,
const CSSToLayerScale& aLayerPixelsPerCSSPixel)
{
// Convert the given rect to layer coordinates so we can inflate to tile
// boundaries (layer space corresponds to texture pixel space here).
LayerRect displayPortInLayerSpace = aDisplayPort * aLayerPixelsPerCSSPixel;
// Inflate the rectangle by 1 so that we always push to the next tile
// boundary. This is desirable to stop from having a rectangle with a
// moving origin occasionally being smaller when it coincidentally lines
// up to tile boundaries.
displayPortInLayerSpace.Inflate(1);
// Now nudge the rectangle to the nearest equal or larger tile boundary.
gfxFloat left = TILEDLAYERBUFFER_TILE_SIZE
* floor(displayPortInLayerSpace.x / TILEDLAYERBUFFER_TILE_SIZE);
gfxFloat top = TILEDLAYERBUFFER_TILE_SIZE
* floor(displayPortInLayerSpace.y / TILEDLAYERBUFFER_TILE_SIZE);
gfxFloat right = TILEDLAYERBUFFER_TILE_SIZE
* ceil(displayPortInLayerSpace.XMost() / TILEDLAYERBUFFER_TILE_SIZE);
gfxFloat bottom = TILEDLAYERBUFFER_TILE_SIZE
* ceil(displayPortInLayerSpace.YMost() / TILEDLAYERBUFFER_TILE_SIZE);
displayPortInLayerSpace = LayerRect(left, top, right - left, bottom - top);
CSSRect displayPort = displayPortInLayerSpace / aLayerPixelsPerCSSPixel;
return displayPort;
}
LayerRect Intersection(const LayerRect &rect1, const LayerRect &rect2) {
LayerRect res;
if (!IsValid(rect1) || !IsValid(rect2)) {
return LayerRect();
}
res.left = MAX(rect1.left, rect2.left);
res.top = MAX(rect1.top, rect2.top);
res.right = MIN(rect1.right, rect2.right);
res.bottom = MIN(rect1.bottom, rect2.bottom);
if (!IsValid(res)) {
return LayerRect();
}
return res;
}
LayerRect Reposition(const LayerRect &rect, const int &x_offset, const int &y_offset) {
LayerRect res;
if (!IsValid(rect)) {
return LayerRect();
}
res.left = rect.left + FLOAT(x_offset);
res.top = rect.top + FLOAT(y_offset);
res.right = rect.right + FLOAT(x_offset);
res.bottom = rect.bottom + FLOAT(y_offset);
return res;
}
