void
ImageTilesState::getMinimalRectsToRenderFromTilesState(const RectI& roi, const TileStateHeader& stateMap, std::list<RectI>* rectsToRender)
{
if (stateMap.state->tiles.empty()) {
return;
}
RectI roiRoundedToTileSize = roi;
roiRoundedToTileSize.roundToTileSize(stateMap.tileSizeX, stateMap.tileSizeY);
RectI bboxM = getMinimalBboxToRenderFromTilesState(roi, stateMap);
if (bboxM.isNull()) {
return;
}
bboxM.roundToTileSize(stateMap.tileSizeX, stateMap.tileSizeY);
// optimization by Fred, Jan 31, 2014
//
// Now that we have the smallest enclosing bounding box,
// let's try to find rectangles for the bottom, the top,
// the left and the right part.
// This happens quite often, for example when zooming out
// (in this case the area to compute is formed of A, B, C and D,
// and X is already rendered), or when panning (in this case the area
// is just two rectangles, e.g. A and C, and the rectangles B, D and
// X are already rendered).
// The rectangles A, B, C and D from the following drawing are just
// zeroes, and X contains zeroes and ones.
//
// BBBBBBBBBBBBBB
// BBBBBBBBBBBBBB
// CXXXXXXXXXXDDD
// CXXXXXXXXXXDDD
// CXXXXXXXXXXDDD
// CXXXXXXXXXXDDD
// AAAAAAAAAAAAAA
// First, find if there's an "A" rectangle, and push it to the result
//find bottom
RectI bboxX = bboxM;
RectI bboxA = bboxX;
bboxA.y2 = bboxA.y1;
for (int y = bboxX.y1; y < bboxX.y2; y += stateMap.tileSizeY) {
bool hasRenderedTileOnLine = false;
for (int x = bboxX.x1; x < bboxX.x2; x += stateMap.tileSizeX) {
const TileState* tile = stateMap.getTileAt(x, y);
if (tile->status != eTileStatusNotRendered) {
hasRenderedTileOnLine = true;
break;
}
}
if (hasRenderedTileOnLine) {
break;
} else {
bboxX.y1 += stateMap.tileSizeY;
bboxA.y2 = bboxX.y1;
}
}
if ( !bboxA.isNull() ) { // empty boxes should not be pushed
// Ensure the bbox lies in the RoI since we rounded to tile size earlier
RectI bboxAIntersected;
bboxA.intersect(roi, &bboxAIntersected);
rectsToRender->push_back(bboxAIntersected);
}
// Now, find the "B" rectangle
//find top
RectI bboxB = bboxX;
bboxB.y1 = bboxB.y2;
for (int y = bboxX.y2 - stateMap.tileSizeY; y >= bboxX.y1; y -= stateMap.tileSizeY) {
bool hasRenderedTileOnLine = false;
for (int x = bboxX.x1; x < bboxX.x2; x += stateMap.tileSizeX) {
const TileState* tile = stateMap.getTileAt(x, y);
if (tile->status != eTileStatusNotRendered) {
hasRenderedTileOnLine = true;
break;
}
}
if (hasRenderedTileOnLine) {
break;
} else {
bboxX.y2 -= stateMap.tileSizeY;
bboxB.y1 = bboxX.y2;
}
}
if ( !bboxB.isNull() ) { // empty boxes should not be pushed
// Ensure the bbox lies in the RoI since we rounded to tile size earlier
RectI bboxBIntersected;
bboxB.intersect(roi, &bboxBIntersected);
rectsToRender->push_back(bboxBIntersected);
}
//find left
RectI bboxC = bboxX;
bboxC.x2 = bboxC.x1;
if ( bboxX.y1 < bboxX.y2 ) {
for (int x = bboxX.x1; x < bboxX.x2; x += stateMap.tileSizeX) {
bool hasRenderedTileOnCol = false;
for (int y = bboxX.y1; y < bboxX.y2; y += stateMap.tileSizeY) {
const TileState* tile = stateMap.getTileAt(x, y);
if (tile->status != eTileStatusNotRendered) {
hasRenderedTileOnCol = true;
break;
}
}
if (hasRenderedTileOnCol) {
break;
} else {
bboxX.x1 += stateMap.tileSizeX;
bboxC.x2 = bboxX.x1;
}
}
}
if ( !bboxC.isNull() ) { // empty boxes should not be pushed
// Ensure the bbox lies in the RoI since we rounded to tile size earlier
RectI bboxCIntersected;
bboxC.intersect(roi, &bboxCIntersected);
rectsToRender->push_back(bboxCIntersected);
}
//find right
RectI bboxD = bboxX;
bboxD.x1 = bboxD.x2;
if ( bboxX.y1 < bboxX.y2 ) {
for (int x = bboxX.x2 - stateMap.tileSizeX; x >= bboxX.x1; x -= stateMap.tileSizeX) {
bool hasRenderedTileOnCol = false;
for (int y = bboxX.y1; y < bboxX.y2; y += stateMap.tileSizeY) {
const TileState* tile = stateMap.getTileAt(x, y);
if (tile->status != eTileStatusNotRendered) {
hasRenderedTileOnCol = true;
break;
}
}
if (hasRenderedTileOnCol) {
break;
} else {
bboxX.x2 -= stateMap.tileSizeX;
bboxD.x1 = bboxX.x2;
}
}
}
if ( !bboxD.isNull() ) { // empty boxes should not be pushed
// Ensure the bbox lies in the RoI since we rounded to tile size earlier
RectI bboxDIntersected;
bboxD.intersect(roi, &bboxDIntersected);
rectsToRender->push_back(bboxDIntersected);
}
assert( bboxA.bottom() == bboxM.bottom() );
assert( bboxA.left() == bboxM.left() );
assert( bboxA.right() == bboxM.right() );
assert( bboxA.top() == bboxX.bottom() );
assert( bboxB.top() == bboxM.top() );
assert( bboxB.left() == bboxM.left() );
assert( bboxB.right() == bboxM.right() );
assert( bboxB.bottom() == bboxX.top() );
assert( bboxC.top() == bboxX.top() );
assert( bboxC.left() == bboxM.left() );
assert( bboxC.right() == bboxX.left() );
assert( bboxC.bottom() == bboxX.bottom() );
assert( bboxD.top() == bboxX.top() );
assert( bboxD.left() == bboxX.right() );
assert( bboxD.right() == bboxM.right() );
assert( bboxD.bottom() == bboxX.bottom() );
// get the bounding box of what's left (the X rectangle in the drawing above)
bboxX = getMinimalBboxToRenderFromTilesState(bboxX, stateMap);
if ( !bboxX.isNull() ) { // empty boxes should not be pushed
// Ensure the bbox lies in the RoI since we rounded to tile size earlier
RectI bboxXIntersected;
bboxX.intersect(roi, &bboxXIntersected);
rectsToRender->push_back(bboxXIntersected);
}
} // getMinimalRectsToRenderFromTilesState
RectI
ImageTilesState::getMinimalBboxToRenderFromTilesState(const RectI& roi, const TileStateHeader& stateMap)
{
if (stateMap.state->tiles.empty()) {
return RectI();
}
const RectI& imageBoundsRoundedToTileSize = stateMap.state->boundsRoundedToTileSize;
const RectI& imageBoundsNotRounded = stateMap.state->bounds;
assert(imageBoundsRoundedToTileSize.contains(roi));
RectI roiRoundedToTileSize = roi;
roiRoundedToTileSize.roundToTileSize(stateMap.tileSizeX, stateMap.tileSizeY);
// Search for rendered lines from bottom to top
for (int y = roiRoundedToTileSize.y1; y < roiRoundedToTileSize.y2; y += stateMap.tileSizeY) {
bool hasTileUnrenderedOnLine = false;
for (int x = roiRoundedToTileSize.x1; x < roiRoundedToTileSize.x2; x += stateMap.tileSizeX) {
const TileState* tile = stateMap.getTileAt(x, y);
if (tile->status == eTileStatusNotRendered) {
hasTileUnrenderedOnLine = true;
break;
}
}
if (!hasTileUnrenderedOnLine) {
roiRoundedToTileSize.y1 += stateMap.tileSizeY;
} else {
break;
}
}
// Search for rendered lines from top to bottom
for (int y = roiRoundedToTileSize.y2 - stateMap.tileSizeY; y >= roiRoundedToTileSize.y1; y -= stateMap.tileSizeY) {
bool hasTileUnrenderedOnLine = false;
for (int x = roiRoundedToTileSize.x1; x < roiRoundedToTileSize.x2; x += stateMap.tileSizeX) {
const TileState* tile = stateMap.getTileAt(x, y);
if (tile->status == eTileStatusNotRendered) {
hasTileUnrenderedOnLine = true;
break;
}
}
if (!hasTileUnrenderedOnLine) {
roiRoundedToTileSize.y2 -= stateMap.tileSizeY;
} else {
break;
}
}
// Avoid making roiRoundedToTileSize.width() iterations for nothing
if (roiRoundedToTileSize.isNull()) {
return roiRoundedToTileSize;
}
// Search for rendered columns from left to right
for (int x = roiRoundedToTileSize.x1; x < roiRoundedToTileSize.x2; x += stateMap.tileSizeX) {
bool hasTileUnrenderedOnCol = false;
for (int y = roiRoundedToTileSize.y1; y < roiRoundedToTileSize.y2; y += stateMap.tileSizeY) {
const TileState* tile = stateMap.getTileAt(x, y);
if (tile->status == eTileStatusNotRendered) {
hasTileUnrenderedOnCol = true;
break;
}
}
if (!hasTileUnrenderedOnCol) {
roiRoundedToTileSize.x1 += stateMap.tileSizeX;
} else {
break;
}
}
// Avoid making roiRoundedToTileSize.width() iterations for nothing
if (roiRoundedToTileSize.isNull()) {
return roiRoundedToTileSize;
}
// Search for rendered columns from right to left
for (int x = roiRoundedToTileSize.x2 - stateMap.tileSizeX; x >= roiRoundedToTileSize.x1; x -= stateMap.tileSizeX) {
bool hasTileUnrenderedOnCol = false;
for (int y = roiRoundedToTileSize.y1; y < roiRoundedToTileSize.y2; y += stateMap.tileSizeY) {
const TileState* tile = stateMap.getTileAt(x, y);
if (tile->status == eTileStatusNotRendered) {
hasTileUnrenderedOnCol = true;
break;
}
}
if (!hasTileUnrenderedOnCol) {
roiRoundedToTileSize.x2 -= stateMap.tileSizeX;
} else {
break;
}
}
// Intersect the result to the actual image bounds (because the tiles are rounded to tile size)
RectI ret;
roiRoundedToTileSize.intersect(imageBoundsNotRounded, &ret);
return ret;
} // getMinimalBboxToRenderFromTilesState
