protected Response returnEmptyTile(final int width, final int height, final String format)
throws Exception {
// return an empty image
ImageResponseWriter writer =
(ImageResponseWriter) ImageHandlerFactory.getHandler(format, ImageResponseWriter.class);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int bands;
Double[] nodatas;
if (format.equalsIgnoreCase("jpg") || format.equalsIgnoreCase("jpeg")) {
bands = 3;
nodatas = new Double[] {0.0, 0.0, 0.0};
} else {
bands = 4;
nodatas = new Double[] {0.0, 0.0, 0.0, 0.0};
}
Raster raster =
RasterUtils.createEmptyRaster(width, height, bands, DataBuffer.TYPE_BYTE, nodatas);
writer.writeToStream(raster, ArrayUtils.toPrimitive(nodatas), baos);
byte[] imageData = baos.toByteArray();
IOUtils.closeQuietly(baos);
final String type = mimeTypeMap.getContentType("output." + format);
return Response.ok(imageData).header("Content-Type", type).build();
// A 404 - Not Found response may be the most appropriate, but results in pink tiles,
// maybe change that behavior on the OpenLayers client?
// return Response.status( Response.Status.NOT_FOUND).build();
}
protected static Response createEmptyTile(
final ImageResponseWriter writer, final int width, final int height) {
// return an empty image
final int dataType;
if (writer.getResponseMimeType().equals("image/jpeg")) {
dataType = BufferedImage.TYPE_3BYTE_BGR;
} else {
// dataType = BufferedImage.TYPE_INT_ARGB;
dataType = BufferedImage.TYPE_4BYTE_ABGR;
}
final BufferedImage bufImg = new BufferedImage(width, height, dataType);
final Graphics2D g = bufImg.createGraphics();
g.setColor(new Color(0, 0, 0, 0));
g.fillRect(0, 0, width, height);
g.dispose();
return writer.write(bufImg.getData()).build();
}