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| <!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8" />
<title></title>
<style>
#canvasa {
display: block;
float: left;
border: 1px solid #aaa;
}
#canvasb {
display: block;
float: right;
border: 1px solid #aaa;
}
</style>
</head>
<body>
<div style="margin: 20px auto; width:1440px;">
<canvas id="canvasa" width="700" height="560"> </canvas>
<canvas id="canvasb" width="700" height="560"> </canvas>
</div>
<div style="clear: both"></div>
<div style="text-align:center; margin-top:50px;font-size:20px;">
<a href="javascript:greyEffect()">Grey Effect</a>
<a href="javascript:blackEffect()">Black and White Effect</a>
<a href="javascript:reverseEffect()">Reverse Effect</a>
<a href="javascript:blurEffect()">Blur Effect</a>
<a href="javascript:mosaicEffect()">Mosaic Effect</a>
</div>
<script>
var canvasa = document.getElementById("canvasa");
var contexta = canvasa.getContext("2d");
var canvasb = document.getElementById("canvasb");
var contextb = canvasb.getContext("2d");
var image = new Image();
window.onload = function () {
image.src = "autumn.jpg";
image.onload = function () {
contexta.drawImage(
image,
0,
0,
canvasa.width,
canvasa.height
);
};
};
function greyEffect() {
var imageData = contexta.getImageData(
0,
0,
canvasa.width,
canvasa.height
);
var pixelData = imageData.data;
for (var i = 0; i < canvasb.width * canvasb.height; i++) {
var r = pixelData[i * 4 + 0];
var g = pixelData[i * 4 + 1];
var b = pixelData[i * 4 + 2];
var grey = r * 0.3 + g * 0.59 + b * 0.11;
pixelData[i * 4 + 0] = grey;
pixelData[i * 4 + 1] = grey;
pixelData[i * 4 + 2] = grey;
}
contextb.putImageData(
imageData,
0,
0,
0,
0,
canvasb.width,
canvasb.height
);
context.putImageData();
}
function blackEffect() {
var imageData = contexta.getImageData(
0,
0,
canvasa.width,
canvasa.height
);
var pixelData = imageData.data;
for (var i = 0; i < canvasb.width * canvasb.height; i++) {
var r = pixelData[i * 4 + 0];
var g = pixelData[i * 4 + 1];
var b = pixelData[i * 4 + 2];
var grey = r * 0.3 + g * 0.59 + b * 0.11;
if (grey > 125) {
pv = 255;
} else {
pv = 0;
}
pixelData[i * 4 + 0] = pv;
pixelData[i * 4 + 1] = pv;
pixelData[i * 4 + 2] = pv;
}
contextb.putImageData(
imageData,
0,
0,
0,
0,
canvasa.width,
canvasa.height
);
}
function reverseEffect() {
var imageData = contexta.getImageData(
0,
0,
canvasa.width,
canvasa.height
);
var pixelData = imageData.data;
for (var i = 0; i < canvasb.width * canvasb.height; i++) {
var r = pixelData[i * 4 + 0];
var g = pixelData[i * 4 + 1];
var b = pixelData[i * 4 + 2];
pixelData[i * 4 + 0] = 255 - r;
pixelData[i * 4 + 1] = 255 - g;
pixelData[i * 4 + 2] = 255 - b;
}
contextb.putImageData(
imageData,
0,
0,
0,
0,
canvasb.width,
canvasb.height
);
}
function blurEffect() {
var tmpImageData = contexta.getImageData(
0,
0,
canvasa.width,
canvasa.height
);
var tmpPixelData = tmpImageData.data;
var imageData = contexta.getImageData(
0,
0,
canvasa.width,
canvasa.height
);
var pixelData = imageData.data;
var blurR = 3;
var totalnum = (2 * blurR + 1) * (2 * blurR + 1);
for (var i = blurR; i < canvasb.height - blurR; i++)
for (var j = blurR; j < canvasb.width - blurR; j++) {
var totalr = 0,
totalg = 0,
totalb = 0;
for (var dx = -blurR; dx <= blurR; dx++)
for (var dy = -blurR; dy <= blurR; dy++) {
var x = i + dx;
var y = j + dy;
var p = x * canvasb.width + y;
totalr += tmpPixelData[p * 4 + 0];
totalg += tmpPixelData[p * 4 + 1];
totalb += tmpPixelData[p * 4 + 2];
}
var p = i * canvasb.width + j;
pixelData[p * 4 + 0] = totalr / totalnum;
pixelData[p * 4 + 1] = totalg / totalnum;
pixelData[p * 4 + 2] = totalb / totalnum;
}
contextb.putImageData(
imageData,
0,
0,
0,
0,
canvasb.width,
canvasb.height
);
}
function mosaicEffect() {
var tmpImageData = contexta.getImageData(
0,
0,
canvasa.width,
canvasa.height
);
var tmpPixelData = tmpImageData.data;
var imageData = contexta.getImageData(
0,
0,
canvasa.width,
canvasa.height
);
var pixelData = imageData.data;
var size = 16;
var totalnum = size * size;
for (var i = 0; i < canvasb.height; i += size)
for (var j = 0; j < canvasb.width; j += size) {
var totalr = 0,
totalg = 0,
totalb = 0;
for (var dx = 0; dx < size; dx++)
for (var dy = 0; dy < size; dy++) {
var x = i + dx;
var y = j + dy;
var p = x * canvasb.width + y;
totalr += tmpPixelData[p * 4 + 0];
totalg += tmpPixelData[p * 4 + 1];
totalb += tmpPixelData[p * 4 + 2];
}
var p = i * canvasb.width + j;
var resr = totalr / totalnum;
var resg = totalg / totalnum;
var resb = totalb / totalnum;
for (var dx = 0; dx < size; dx++)
for (var dy = 0; dy < size; dy++) {
var x = i + dx;
var y = j + dy;
var p = x * canvasb.width + y;
pixelData[p * 4 + 0] = resr;
pixelData[p * 4 + 1] = resg;
pixelData[p * 4 + 2] = resb;
}
}
contextb.putImageData(
imageData,
0,
0,
0,
0,
canvasb.width,
canvasb.height
);
}
</script>
</body>
</html>
|
