protected void renderCanvas() throws OutsideCoverageException, GeoWebCacheException, IOException {
// Now we loop over all the relevant tiles and write them to the canvas,
// Starting at the bottom, moving to the right and up
// Bottom row of tiles, in tile coordinates
long starty = srcRectangle[1];
// gridy is the tile row index
for (long gridy = starty; gridy <= srcRectangle[3]; gridy++) {
int tiley = 0;
int canvasy = (int) (srcRectangle[3] - gridy) * gridSubset.getTileHeight();
int tileHeight = gridSubset.getTileHeight();
if (canvOfs.top > 0) {
// Add padding
canvasy += canvOfs.top;
} else {
// Top tile is cut off
if (gridy == srcRectangle[3]) {
// This one starts at the top, so canvasy remains 0
tileHeight = tileHeight + canvOfs.top;
tiley = -canvOfs.top;
} else {
// Offset that the first tile contributed,
// rather, we subtract what it did not contribute
canvasy += canvOfs.top;
}
}
if (gridy == srcRectangle[1] && canvOfs.bottom < 0) {
// Check whether we only use part of the first tiles (bottom row)
// Offset is negative, slice the bottom off the tile
tileHeight += canvOfs.bottom;
}
long startx = srcRectangle[0];
for (long gridx = startx; gridx <= srcRectangle[2]; gridx++) {
long[] gridLoc = {gridx, gridy, srcIdx};
ConveyorTile tile =
new ConveyorTile(
sb,
layer.getName(),
gridSubset.getName(),
gridLoc,
ImageMime.png,
fullParameters,
null,
null);
// Check whether this tile is to be rendered at all
try {
layer.applyRequestFilters(tile);
} catch (RequestFilterException e) {
log.debug(e.getMessage());
continue;
}
layer.getTile(tile);
BufferedImage tileImg = ImageIO.read(tile.getBlob().getInputStream());
int tilex = 0;
int canvasx = (int) (gridx - startx) * gridSubset.getTileWidth();
int tileWidth = gridSubset.getTileWidth();
if (canvOfs.left > 0) {
// Add padding
canvasx += canvOfs.left;
} else {
// Leftmost tile is cut off
if (gridx == srcRectangle[0]) {
// This one starts to the left top, so canvasx remains 0
tileWidth = tileWidth + canvOfs.left;
tilex = -canvOfs.left;
} else {
// Offset that the first tile contributed,
// rather, we subtract what it did not contribute
canvasx += canvOfs.left;
}
}
if (gridx == srcRectangle[2] && canvOfs.right < 0) {
// Check whether we only use part of the first tiles (bottom row)
// Offset is negative, slice the bottom off the tile
tileWidth = tileWidth + canvOfs.right;
}
// TODO We should really ensure we can never get here
if (tileWidth == 0 || tileHeight == 0) {
log.debug("tileWidth: " + tileWidth + " tileHeight: " + tileHeight);
continue;
}
// Cut down the tile to the part we want
if (tileWidth != gridSubset.getTileWidth() || tileHeight != gridSubset.getTileHeight()) {
log.debug(
"tileImg.getSubimage("
+ tilex
+ ","
+ tiley
+ ","
+ tileWidth
+ ","
+ tileHeight
+ ")");
tileImg = tileImg.getSubimage(tilex, tiley, tileWidth, tileHeight);
}
// Render the tile on the big canvas
log.debug(
"drawImage(subtile," + canvasx + "," + canvasy + ",null) " + Arrays.toString(gridLoc));
gfx.drawImage(tileImg, canvasx, canvasy, null); // imageObserver
}
}
gfx.dispose();
}
