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/**
* Copyright 2009 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS-IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import("blob");
jimport("java.awt.image.BufferedImage");
jimport("org.apache.sanselan.Sanselan");
jimport("org.apache.sanselan.ImageFormat");
if (java.lang.System.getProperty("java.awt.headless") == null) {
// If the system property isn't set either way, then default to "headless" mode,
// so that we don't start calling the window manager when the AWT classes
// are loaded. For example, on OS X the java process is given a Dock icon
// when we create our first BufferedImage.
java.lang.System.setProperty("java.awt.headless", "true");
}
/**
* Encodes the given pixel data into an image blob, ready to be served to
* the client. Pixels are specified as 32-bit ints in the format AARRGGBB,
* and the order is across rows first, then down columns. If useTransparency
* is true, then all pixels should have an alpha channel as their
* most-significant byte, with 0xff being fully opaque. If useTransparency
* is false, all pixels are fully opaque and the high byte is ignored.
* Supported formats: GIF.
* <p>
* For example, to create a GIF image consisting of a green pixel followed
* by a transparent pixel to the right of it, use:
* imageBlobFromPixels(2, 1, [0xff00ff00, 0x00000000], true, "gif")
*/
function pixelsToImageBlob(width, height, pixelArrayARGB, useTransparency, format) {
var image = _makeBufferedImage(width, height);
var array = _makePixelArray(width, height);
var alphaMask = (useTransparency ? 0x00000000 : 0xff000000);
for(var i=0; i<array.length; i++) {
// bitwise operations cause a JS number to become a signed 32-bit int
array[i] = (pixelArrayARGB[i] | alphaMask);
}
_setImagePixels(image, array);
if (format.toLowerCase() == "gif") {
return _bufferedImage2gifBlob(image);
}
return null;
}
/**
* Creates a blob of image data in a format readable by a web browser
* that consists of a solid, opaque color and has the given width
* and height. The sixHexDigits must be a number, such as
* 0x12fda3, or a string, such as "12fda3".
*/
function solidColorImageBlob(width, height, sixHexDigits) {
var image = _makeBufferedImage(width, height);
var array = _makePixelArray(width, height);
var pixel = 0xffffff;
if ((typeof sixHexDigits) == "number") {
pixel = sixHexDigits;
}
else if ((typeof sixHexDigits) == "string") {
pixel = Number("0x"+sixHexDigits);
}
// bitwise operations cause a JS number to become a signed 32-bit int
pixel = ((pixel & 0xffffff) | 0xff000000);
java.util.Arrays.fill(array, pixel);
_setImagePixels(image, array);
return _bufferedImage2gifBlob(image);
}
function _makeBufferedImage(width, height) {
return new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
}
function _makePixelArray(width, height) {
return java.lang.reflect.Array.newInstance(java.lang.Integer.TYPE,
width*height);
}
function _setImagePixels(image, array) {
var width = image.getWidth();
var height = image.getHeight();
image.setRGB(0, 0, width, height, array, 0, width);
}
function _bufferedImage2gifBlob(image) {
// Use the Apache Sanselan image library because it nails transparent GIFs.
var bytes = Sanselan.writeImageToBytes(image, ImageFormat.IMAGE_FORMAT_GIF, null);
return blob.byteArrayToBlob("image/gif", bytes);
}
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