Javascript 使用画布调整6角图像大小
我有两个问题:Javascript 使用画布调整6角图像大小,javascript,html,css,canvas,Javascript,Html,Css,Canvas,我有两个问题: 上止点、下止点、左止点和右止点没有被剪掉 我没有得到改变图像大小的逻辑。 角锚点应按比例调整大小(高度和宽度,两者应以相同的速率减少/增加) 非转弯的应相应调整大小,如下图所示 这是我预期的实施: 我已经创建了一个画布,在上面我画了一个图像并调整了它的大小 下面是脚本: var canvas = document.getElementById("canvas"); var ctx = canvas.getContext("2d"); //var canvasOffset
下面是脚本:
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
//var canvasOffset = $("#canvas").offset();
var offsetX = canvas.offsetLeft;
var offsetY = canvas.offsetTop;
var startX;
var startY;
var isDown = false;
var pi2 = Math.PI * 2;
var resizerRadius = 8;
var rr = resizerRadius * resizerRadius;
var draggingResizer = {
x: 0,
y: 0
};
var imageX = 50;
var imageY = 50;
var imageWidth, imageHeight, imageRight, imageBottom;
var draggingImage = false;
var startX;
var startY;
var img = new Image();
img.onload = function () {
imageWidth = img.width;
imageHeight = img.height;
imageRight = imageX + imageWidth;
imageBottom = imageY + imageHeight
draw(true, false);
}
img.src = 'img/' + localStorage["bgimgname"];
function draw(withAnchors, withBorders) {
// clear the canvas
ctx.clearRect(0, 0, canvas.width, canvas.height);
// draw the image
ctx.drawImage(img, 0, 0, img.width, img.height, imageX, imageY, imageWidth, imageHeight);
// optionally draw the draggable anchors
if (withAnchors) {
drawDragAnchor(imageX, imageY); //topleft
drawDragAnchor((imageRight+imageX)/2, imageY); //topcenter
drawDragAnchor(imageRight, imageY); //topright
drawDragAnchor(imageX, (imageBottom+imageY)/2); //left
drawDragAnchor(imageRight, (imageBottom+imageY)/2); //right
drawDragAnchor(imageX, imageBottom); //bottomleft
drawDragAnchor((imageRight+imageX)/2, imageBottom); //bottom center
drawDragAnchor(imageRight, imageBottom); //bottomright
}
// optionally draw the connecting anchor lines
if (withBorders) {
ctx.beginPath();
ctx.moveTo(imageX, imageY);
ctx.lineTo(imageRight, imageY);
ctx.lineTo(imageRight, imageBottom);
ctx.lineTo(imageX, imageBottom);
ctx.closePath();
ctx.stroke();
}
}
function drawDragAnchor(x, y) {
ctx.beginPath();
ctx.arc(x, y, resizerRadius, 0, pi2, false);
ctx.closePath();
ctx.fill();
}
function anchorHitTest(x, y) {
var dx, dy;
// top-left
dx = x - imageX;
dy = y - imageY;
if (dx * dx + dy * dy <= rr) {
return (0);
}
// top-center
dx = (imageRight+imageX)/2
dy = imageY
if (dx/2 * dx/2 + dy * dy <= rr) {
return (1);
}
// top-right
dx = x - imageRight;
dy = y - imageY;
if (dx * dx + dy * dy <= rr) {
return (2);
}
//left
dx = imageX;
dy = (imageBottom+imageY)/2
if (dx * dx + dy/2 * dy/2 <= rr) {
return (3);
}
//right
dx = imageRight;
dy = (imageBottom+imageY)/2
if (dx * dx + dy/2 * dy/2 <= rr) {
return (4);
}
// bottom-right
dx = x - imageRight;
dy = y - imageBottom;
if (dx * dx + dy * dy <= rr) {
return (5);
}
// bottom-center
dx = (imageRight+imageX)/2;
dy = imageBottom;
if (dx/2 * dx/2 + dy * dy <= rr) {
return (6);
}
// bottom-left
dx = x - imageX;
dy = y - imageBottom;
if (dx * dx + dy * dy <= rr) {
return (7);
}
return (-1);
}
function hitImage(x, y) {
return (x > imageX && x < imageX + imageWidth && y > imageY && y < imageY + imageHeight);
}
function handleMouseDown(e) {
startX = parseInt(e.clientX - offsetX);
startY = parseInt(e.clientY - offsetY);
draggingResizer = anchorHitTest(startX, startY);
draggingImage = draggingResizer < 0 && hitImage(startX, startY);
}
function handleMouseUp(e) {
draggingResizer = -1;
draggingImage = false;
draw(true, false);
}
function handleMouseOut(e) {
handleMouseUp(e);
}
function handleMouseMove(e) {
e = window.event;
if (draggingResizer > -1) {
mouseX = parseInt(e.clientX - offsetX);
mouseY = parseInt(e.clientY - offsetY);
// resize the image
switch (draggingResizer) {
case 0:
//top-left
console.log("topleft");
break;
case 1:
//top-center
console.log("topcenter");
break;
case 2:
//top-right
console.log("topright");
break;
case 3:
//left
console.log("left");
break;
case 4:
//right
console.log("right");
break;
case 5:
//bottom-left
console.log("bottomleft");
break;
case 6:
//center
console.log("bottomcenter");
break;
case 7:
//bottom-right
console.log("bottomright");
break;
}
if(imageWidth<25){imageWidth=25;}
if(imageHeight<25){imageHeight=25;}
if(imageWidth>700){imageWidth=700;}
if(imageHeight>700){imageHeight=700;}
// set the image right and bottom
imageRight = imageX + imageWidth;
imageBottom = imageY + imageHeight;
// redraw the image with resizing anchors
draw(true, true);
}
}
canvas.addEventListener('mousedown', handleMouseDown);
canvas.addEventListener('mousemove', handleMouseMove);
canvas.addEventListener('mouseup', handleMouseUp);
canvas.addEventListener('mouseout', handleMouseOut);
var canvas=document.getElementById(“canvas”);
var ctx=canvas.getContext(“2d”);
//var canvasOffset=$(“#画布”).offset();
var offsetX=canvas.offsetLeft;
var offsetY=canvas.offsetTop;
var-startX;
var startY;
var isDown=假;
var pi2=Math.PI*2;
var resizerRadius=8;
var rr=resizerRadius*resizerRadius;
变量拖动器={
x:0,,
y:0
};
var-imageX=50;
var imageY=50;
变量imageWidth、imageHeight、imageRight、imageBottom;
var draggingImage=false;
var-startX;
var startY;
var img=新图像();
img.onload=函数(){
imageWidth=img.width;
图像高度=图像高度;
imageRight=imageX+imageWidth;
imageBottom=imageY+imageHeight
画(真、假);
}
img.src='img/'+localStorage[“bgimgname”];
函数绘制(带锚定、带边框){
//清理画布
clearRect(0,0,canvas.width,canvas.height);
//画图像
ctx.drawImage(img,0,0,img.width,img.height,imageX,imageY,imageWidth,imageHeight);
//(可选)绘制可拖动的锚点
如果(带锚){
drawDragAnchor(imageX,imageY);//左上角
drawDragAnchor((imageRight+imageX)/2,imageY);//topcenter
drawDragAnchor(imageRight,imageY);//右上角
drawDragAnchor(imageX,(imageBottom+imageY)/2);//左
drawDragAnchor(imageRight,(imageBottom+imageY)/2);//右
drawDragAnchor(imageX,imageBottom);//左下角
drawDragAnchor((imageRight+imageX)/2,imageBottom);//底部中心
drawDragAnchor(imageRight,imageBottom);//bottomright
}
//(可选)绘制连接锚定线
如果(带边框){
ctx.beginPath();
ctx.moveTo(imageX,imageY);
ctx.lineTo(imageRight,imageY);
ctx.lineTo(图像右侧,图像底部);
ctx.lineTo(imageX,imageBottom);
ctx.closePath();
ctx.stroke();
}
}
函数drawDragAnchor(x,y){
ctx.beginPath();
ctx.弧(x,y,resizerRadius,0,pi2,false);
ctx.closePath();
ctx.fill();
}
功能测试(x,y){
var-dx,dy;
//左上角
dx=x-图像x;
dy=y-imageY;
如果(dx*dx+dy*dy见我的答案:
我在重复下面的答案,以防有人用谷歌搜索这个答案而不是另一个
根据需要调整大小的一种有效方法是保持相对侧的位置固定,并让选定侧与拖动侧或角一起浮动
这种方法的一个附带好处是,您实际上不需要锚
这就是操作系统windows的工作方式
调整窗口大小时,如果没有可拖动的可见定位点,只需拖动窗口的边或角即可
演示:
- 左:原始图像
- 中间:从左下角调整大小并保持纵横比(右上角保持固定)
- 右侧:从底部调整大小&图像仅沿y方向缩放(图像顶部保持固定)
注意:此演示和示例显示锚定,但它们完全是装饰性的。您可以关闭锚定显示,并通过拖动图像的一侧或角来调整图像大小
示例代码:
<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
<style>
body{ background-color: ivory; }
canvas{border:1px solid red;}
</style>
<script>
$(function(){
var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");
var $canvas=$("#canvas");
var canvasOffset=$canvas.offset();
var offsetX=canvasOffset.left;
var offsetY=canvasOffset.top;
var isDown=false;
var iW;
var iH;
var iLeft=50;
var iTop=50;
var iRight,iBottom,iOrientation;
var img=new Image();
img.onload=function(){
iW=img.width;
iH=img.height;
iRight=iLeft+iW;
iBottom=iTop+iH;
iOrientation=(iW>=iH)?"Wide":"Tall";
draw(true);
}
img.src="facesSmall.png";
var border=10;
var isLeft=false;
var isRight=false;
var isTop=false;
var isBottom=false;
var iAnchor;
canvas.onmousedown=handleMousedown;
canvas.onmousemove=handleMousemove;
canvas.onmouseup=handleMouseup;
canvas.onmouseout=handleMouseup;
function hitResizeAnchor(x,y){
// which borders are under the mouse
isLeft=(x>iLeft && x<iLeft+border);
isRight=(x<iRight && x>iRight-border);
isTop=(y>iTop && y<iTop+border);
isBottom=(y<iBottom && y>iBottom-border);
// return the appropriate anchor
if(isTop && isLeft){ return(iOrientation+"TL"); }
if(isTop && isRight){ return(iOrientation+"TR"); }
if(isBottom && isLeft){ return(iOrientation+"BL"); }
if(isBottom && isRight){ return(iOrientation+"BR"); }
if(isTop){ return("T"); }
if(isRight){ return("R"); }
if(isBottom){ return("B"); }
if(isLeft){ return("L"); }
return(null);
}
var resizeFunctions={
T: function(x,y){ iTop=y; },
R: function(x,y){ iRight=x; },
B: function(x,y){ iBottom=y; },
L: function(x,y){ iLeft=x; },
WideTR: function(x,y){
iRight=x;
iTop=iBottom-(iH*(iRight-iLeft)/iW);
},
TallTR: function(x,y){
iTop=y;
iRight=iLeft+(iW*(iBottom-iTop)/iH);
},
WideBR: function(x,y){
iRight=x;
iBottom=iTop+(iH*(iRight-iLeft)/iW);
},
TallBR: function(x,y){
iBottom=y;
iRight=iLeft+(iW*(iBottom-iTop)/iH);
},
WideBL: function(x,y){
iLeft=x;
iBottom=iTop+(iH*(iRight-iLeft)/iW);
},
TallBL: function(x,y){
iBottom=y;
iLeft=iRight-(iW*(iBottom-iTop)/iH);
},
WideTL: function(x,y){
iLeft=x;
iTop=iBottom-(iH*(iRight-iLeft)/iW);
},
TallTL: function(x,y){
iBottom=y;
iLeft=iRight-(iW*(iBottom-iTop)/iH);
}
};
function handleMousedown(e){
// tell the browser we'll handle this mousedown
e.preventDefault();
e.stopPropagation();
var mouseX=e.clientX-offsetX;
var mouseY=e.clientY-offsetY;
iAnchor=hitResizeAnchor(mouseX,mouseY);
isDown=(iAnchor);
}
function handleMouseup(e){
// tell the browser we'll handle this mouseup
e.preventDefault();
e.stopPropagation();
isDown=false;
draw(true);
}
function handleMousemove(e){
// tell the browser we'll handle this mousemove
e.preventDefault();
e.stopPropagation();
// return if we're not dragging
if(!isDown){return;}
// get MouseX/Y
var mouseX=e.clientX-offsetX;
var mouseY=e.clientY-offsetY;
// reset iLeft,iRight,iTop,iBottom based on drag
resizeFunctions[iAnchor](mouseX,mouseY);
// redraw the resized image
draw(false);
}
function draw(withAnchors){
var cx=iLeft+(iRight-iLeft)/2;
var cy=iTop+(iBottom-iTop)/2;
ctx.clearRect(0,0,canvas.width,canvas.height);
ctx.drawImage(img,iLeft,iTop,iRight-iLeft,iBottom-iTop);
if(withAnchors){
ctx.fillRect(iLeft,iTop,border,border);
ctx.fillRect(iRight-border,iTop,border,border);
ctx.fillRect(iRight-border,iBottom-border,border,border);
ctx.fillRect(iLeft,iBottom-border,border,border);
ctx.fillRect(cx,iTop,border,border);
ctx.fillRect(cx,iBottom-border,border,border);
ctx.fillRect(iLeft,cy,border,border);
ctx.fillRect(iRight-border,cy,border,border);
}
}
}); // end $(function(){});
</script>
</head>
<body>
<h4>Drag image anchors</h4>
<canvas id="canvas" width=300 height=300></canvas>
</body>
</html>
正文{背景色:象牙;}
画布{边框:1px纯红;}
$(函数(){
var canvas=document.getElementById(“canvas”);
var ctx=canvas.getContext(“2d”);
var$canvas=$(“#canvas”);
var canvasOffset=$canvas.offset();
var offsetX=canvasOffset.left;
var offsetY=canvasOffset.top;
var isDown=假;
var-iW;
var-iH;
var iLeft=50;
var-iTop=50;
var iRight、iBottom、iOrientation;
var img=新图像();
img.onload=函数(){
iW=img.宽度;
iH=img.高度;
iRight=iLeft+iW;
iBottom=iTop+iH;
I方向=(iW>=iH)?“宽”:“高”;
画(真);
}
img.src=“facesSmall.png”;
var-border=10;
var isLeft=false;
var isRight=false;
var-isTop=false;
var isBottom=false;
var iAnchor;
canvas.onmousedown=handleMousedown;
canvas.onmousemove=handleMousemove;
canvas.onmouseup=handleMouseup;
canvas.onmouseout=handleMouseup;
函数hitResizeAnchor(x,y){
//鼠标下有哪些边框
isLeft=(x>iLeft&&xiTop&&y有什么方法可以使它也可以移动吗?当然——很简单!图像的位置也由iLeft/iRight和iTop/iBottom变量控制。例如,如果要将图像向右移动10个像素:iLeft+=10;iRight+=10;draw();
<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
<style>
body{ background-color: ivory; }
canvas{border:1px solid red;}
</style>
<script>
$(function(){
var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");
var $canvas=$("#canvas");
var canvasOffset=$canvas.offset();
var offsetX=canvasOffset.left;
var offsetY=canvasOffset.top;
var isDown=false;
var iW;
var iH;
var iLeft=50;
var iTop=50;
var iRight,iBottom,iOrientation;
var img=new Image();
img.onload=function(){
iW=img.width;
iH=img.height;
iRight=iLeft+iW;
iBottom=iTop+iH;
iOrientation=(iW>=iH)?"Wide":"Tall";
draw(true);
}
img.src="facesSmall.png";
var border=10;
var isLeft=false;
var isRight=false;
var isTop=false;
var isBottom=false;
var iAnchor;
canvas.onmousedown=handleMousedown;
canvas.onmousemove=handleMousemove;
canvas.onmouseup=handleMouseup;
canvas.onmouseout=handleMouseup;
function hitResizeAnchor(x,y){
// which borders are under the mouse
isLeft=(x>iLeft && x<iLeft+border);
isRight=(x<iRight && x>iRight-border);
isTop=(y>iTop && y<iTop+border);
isBottom=(y<iBottom && y>iBottom-border);
// return the appropriate anchor
if(isTop && isLeft){ return(iOrientation+"TL"); }
if(isTop && isRight){ return(iOrientation+"TR"); }
if(isBottom && isLeft){ return(iOrientation+"BL"); }
if(isBottom && isRight){ return(iOrientation+"BR"); }
if(isTop){ return("T"); }
if(isRight){ return("R"); }
if(isBottom){ return("B"); }
if(isLeft){ return("L"); }
return(null);
}
var resizeFunctions={
T: function(x,y){ iTop=y; },
R: function(x,y){ iRight=x; },
B: function(x,y){ iBottom=y; },
L: function(x,y){ iLeft=x; },
WideTR: function(x,y){
iRight=x;
iTop=iBottom-(iH*(iRight-iLeft)/iW);
},
TallTR: function(x,y){
iTop=y;
iRight=iLeft+(iW*(iBottom-iTop)/iH);
},
WideBR: function(x,y){
iRight=x;
iBottom=iTop+(iH*(iRight-iLeft)/iW);
},
TallBR: function(x,y){
iBottom=y;
iRight=iLeft+(iW*(iBottom-iTop)/iH);
},
WideBL: function(x,y){
iLeft=x;
iBottom=iTop+(iH*(iRight-iLeft)/iW);
},
TallBL: function(x,y){
iBottom=y;
iLeft=iRight-(iW*(iBottom-iTop)/iH);
},
WideTL: function(x,y){
iLeft=x;
iTop=iBottom-(iH*(iRight-iLeft)/iW);
},
TallTL: function(x,y){
iBottom=y;
iLeft=iRight-(iW*(iBottom-iTop)/iH);
}
};
function handleMousedown(e){
// tell the browser we'll handle this mousedown
e.preventDefault();
e.stopPropagation();
var mouseX=e.clientX-offsetX;
var mouseY=e.clientY-offsetY;
iAnchor=hitResizeAnchor(mouseX,mouseY);
isDown=(iAnchor);
}
function handleMouseup(e){
// tell the browser we'll handle this mouseup
e.preventDefault();
e.stopPropagation();
isDown=false;
draw(true);
}
function handleMousemove(e){
// tell the browser we'll handle this mousemove
e.preventDefault();
e.stopPropagation();
// return if we're not dragging
if(!isDown){return;}
// get MouseX/Y
var mouseX=e.clientX-offsetX;
var mouseY=e.clientY-offsetY;
// reset iLeft,iRight,iTop,iBottom based on drag
resizeFunctions[iAnchor](mouseX,mouseY);
// redraw the resized image
draw(false);
}
function draw(withAnchors){
var cx=iLeft+(iRight-iLeft)/2;
var cy=iTop+(iBottom-iTop)/2;
ctx.clearRect(0,0,canvas.width,canvas.height);
ctx.drawImage(img,iLeft,iTop,iRight-iLeft,iBottom-iTop);
if(withAnchors){
ctx.fillRect(iLeft,iTop,border,border);
ctx.fillRect(iRight-border,iTop,border,border);
ctx.fillRect(iRight-border,iBottom-border,border,border);
ctx.fillRect(iLeft,iBottom-border,border,border);
ctx.fillRect(cx,iTop,border,border);
ctx.fillRect(cx,iBottom-border,border,border);
ctx.fillRect(iLeft,cy,border,border);
ctx.fillRect(iRight-border,cy,border,border);
}
}
}); // end $(function(){});
</script>
</head>
<body>
<h4>Drag image anchors</h4>
<canvas id="canvas" width=300 height=300></canvas>
</body>
</html>