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<!DOCTYPE html>
<html>
<head>
<meta charset= "utf-8" />
<title>Grayscale Windowing Test</title>
<style type= "text/css" >
table {margin:auto;}
</style>
</head>
<body>
<table>
<tr align= "center" ><td><h3>Grayscale Image Test</h3><hr height= "1px" /></td>
</tr>
<tr>
<td align= "right" >
WW(<span id= "spanWW" ></span>): <input id= "rangeWW" type= "range" min= "0" max= "4096" onchange= "setWindow();" />
WC(<span id= "spanWC" ></span>): <input id= "rangeWC" type= "range" min= "0" max= "4096" onchange= "setWindow();" />
<button id= "resetImage" onclick= "loadImage();return true;" >Reset</button>
</td>
</tr>
<tr align= "center" >
<td><canvas id= "imageviewer" width= "512px" height= "512px" style= "border: 1px solid;" mce_style= "border: 1px solid;" /></td>
</tr>
<tr align= "center" ><td>© May, 2011, lifegame@263.net</td>
</tr>
</table>
</body>
<script>
var patternData = [];
var patternWidth = 512;
var patternHeight = 512;
var patternMaxGray = 0x0FFF;
function getPatternData(x,y){
return patternData[y*patternWidth+x];
}
function setPatternData(x,y,v){
patternData[y*patternWidth+x]=v;
}
function initPatternData(){
function fillRect(x,y,w,h,v){
var maxX = x+w;
var maxY = y+h;
for (i=x;i<maxX;i++){
for (j=y;j<maxY;j++){
setPatternData(i,j,v);
}
}
}
function fillGradientRect(x,y,w,h,f,t){
var maxX = x+w;
var maxY = y+h;
for (i=x;i<maxX;i++){
var v = f+Math.round((t-f)*(i-x)/w);
for (j=y;j<maxY;j++){
setPatternData(i,j,v);
}
}
}
function fillGrid(c,r,v){
var x = c*128;
var y = r*128;
fillRect(x,y,128,128,v);
}
function fillGradientGrid(c,r,f,t){
var x = c*128;
var y = r*128;
fillGradientRect(x,y,128,128,f,t);
}
function drawLines(x,y,w,h,d){
var v;
var maxX = x+w;
var maxY = y+h;
if (d==1){
for (i=x;i<maxX;i++){
v = ((i%2)==0)? 0 : patternMaxGray;
for (j=y;j<maxY;j++){
setPatternData(i,j,v);
}
}
}
else {
for (i=y;i<maxY;i++){
v = ((i%2)==0)? 0 : patternMaxGray;
for (j=x;j<maxX;j++){
setPatternData(j,i,v);
}
}
}
}
function fillLineGrid(c,r){
var x = c*128;
var y = r*128;
drawLines(x,y,64,128,1);
drawLines(x+64,y,64,128,0);
}
fillGrid(0,0,0);
fillRect(32,32,64,64,patternMaxGray*0.05);
fillGrid(1,0,patternMaxGray*0.1);
fillGrid(2,0,patternMaxGray*0.2);
fillGrid(3,0,patternMaxGray*0.3);
fillGrid(0,1,patternMaxGray*0.4);
fillGrid(1,1,patternMaxGray*0.5);
fillGrid(2,1,patternMaxGray*0.6);
fillGrid(3,1,patternMaxGray*0.7);
fillGrid(0,2,patternMaxGray*0.8);
fillGrid(1,2,patternMaxGray*0.9);
fillGrid(2,2,patternMaxGray);
fillRect(256+32,256+32,64,64,patternMaxGray*0.95);
fillLineGrid(3,2);
fillGradientGrid(0,3,0,patternMaxGray/4);
fillGradientGrid(1,3,patternMaxGray/4,patternMaxGray*2/4);
fillGradientGrid(2,3,patternMaxGray*2/4,patternMaxGray*3/4);
fillGradientGrid(3,3,patternMaxGray*3/4,patternMaxGray);
}
</script>
<script>
var icanvas = document.getElementById( 'imageviewer' );
var icanvasWidth = parseInt(icanvas.getAttribute( "width" ));
var icanvasHeight = parseInt(icanvas.getAttribute( "height" ));
var icontext = icanvas.getContext( '2d' );
var isWindowing = 0;
var beginPointX = 0;
var beginPointY = 0;
var wwStep = 5;
var wcStep = 5;
function loadImage(){
icanvas.onmousedown = function (e){
isWindowing = 1;
if (e.offsetX) {
beginPointX = e.offsetX;
beginPointY = e.offsetY;
}
else if (e.layerX) {
beginPointX = e.layerX;
beginPointY = e.layerY;
}
}
icanvas.onmouseup = function (e){
isWindowing = 0;
if (e.offsetX) {
x = e.offsetX;
y = e.offsetY;
}
else if (e.layerX) {
x = e.layerX;
y = e.layerY;
}
var ww = parseInt(rangeWW.value);
var wc = parseInt(rangeWC.value);
ww = ww+(x-beginPointX)*wwStep;
wc = wc+(y-beginPointY)*wcStep;
updateWindow(ww,wc);
}
function updateWindow(ww,wc){
loadPattern(ww,wc);
rangeWW.value = ww;
rangeWC.value = wc;
spanWW.innerHTML = ww;
spanWC.innerHTML = wc;
}
initPatternData();
updateWindow(4096,2048);
}
function loadPattern(ww,wc){
function setPoint(img,x,y,pv){
var i = (y*img.width+x)*4;
img.data[i]=img.data[i+1]=img.data[i+2]=pv;
img.data[i+3]=255;
}
function getPresentationValue(v,w,c){
var minv = c-Math.round(w/2);
if (v<minv) return 0;
var maxv = c+Math.round(w/2);
if (v>maxv) return 255;
var pv = Math.round(255*(v-minv)/w);
if (pv<0) return 0;
if (pv>255) return 255;
return pv;
}
var imgData = icontext.getImageData(0,0,icanvasWidth,icanvasHeight);
for (y=0;y<patternHeight;y++){
if (y>=imgData.height) break ;
for (x=0;x<patternWidth;x++){
if (x>=imgData.width) break ;
var v = getPatternData(x,y);
var pv = getPresentationValue(v,ww,wc);
setPoint(imgData,x,y,pv);
}
}
icontext.putImageData(imgData,0,0);
}
function setWindow(){
var ww = parseInt(rangeWW.value);
var wc = parseInt(rangeWC.value);
loadPattern(ww,wc);
spanWW.innerHTML = ww;
spanWC.innerHTML = wc;
}
window.addEventListener( "load" , loadImage(), true );
</script>
<html>
|
(责任编辑:12图资源库)