好的,所以我很欣赏这是一个非常基本的问题,但我对画布来说是全新的,我只需要做一些简单的事情。基本上我使用springy.js来绘制力导向图。图表上的节点是正方形,我只想让它们成为圆形。有人可以告诉我在下面的代码中我应该改变什么,我可以从那里找出其余的
我试过
ctx.arc(s.x - boxWidth/2, s.y - boxHeight/2, boxWidth, boxHeight,2*Math.PI);
ctx.stroke();
而不是带有clearRect的行,但是框保持不变,框之间的连接不再是直线。
function drawNode(node, p) {
var s = toScreen(p);
ctx.save();
// Pulled out the padding aspect sso that the size functions could be used in multiple places
// These should probably be settable by the user (and scoped higher) but this suffices for now
var paddingX = 6;
var paddingY = 6;
var contentWidth = node.getWidth();
var contentHeight = node.getHeight();
var boxWidth = contentWidth + paddingX;
var boxHeight = contentHeight + paddingY;
// clear background
ctx.clearRect(s.x - boxWidth/2, s.y - boxHeight/2, boxWidth, boxHeight);
// fill background
if (selected !== null && selected.node !== null && selected.node.id === node.id) {
ctx.fillStyle = "#FFFFE0"; //when clicked
} else if (nearest !== null && nearest.node !== null && nearest.node.id === node.id) {
ctx.fillStyle = "#EEEEEE";//when hovered over
} else {
//if the node.FBScore >10 then ctx.fillStyle = "#F00909";
ctx.fillStyle = "#E34747";//normal colour
}
ctx.fillRect(s.x - boxWidth/2, s.y - boxHeight/2, boxWidth, boxHeight);
if (node.data.image == undefined) {
ctx.textAlign = "left";
ctx.textBaseline = "top";
ctx.font = (node.data.font !== undefined) ? node.data.font : nodeFont;
ctx.fillStyle = (node.data.color !== undefined) ? node.data.color : "#000000";
var text = (node.data.label !== undefined) ? node.data.label : node.id;
ctx.fillText(text, s.x - contentWidth/2, s.y - contentHeight/2);
} else {
// Currently we just ignore any labels if the image object is set. One might want to extend this logic to allow for both, or other composite nodes.
var src = node.data.image.src; // There should probably be a sanity check here too, but un-src-ed images aren't exaclty a disaster.
if (src in nodeImages) {
if (nodeImages[src].loaded) {
// Our image is loaded, so it's safe to draw
ctx.drawImage(nodeImages[src].object, s.x - contentWidth/2, s.y - contentHeight/2, contentWidth, contentHeight);
}
}else{
// First time seeing an image with this src address, so add it to our set of image objects
// Note: we index images by their src to avoid making too many duplicates
nodeImages[src] = {};
var img = new Image();
nodeImages[src].object = img;
img.addEventListener("load", function () {
// HTMLImageElement objects are very finicky about being used before they are loaded, so we set a flag when it is done
nodeImages[src].loaded = true;
});
img.src = src;
}
}
ctx.restore();
}
答案 0 :(得分:1)
您应该将clearRect()
替换为fillRect()
,而不是替换arc(x, y, radius, startAngle, endAngle, anticlockwise);
方法:
var canvas = document.querySelector('canvas');
var ctx = canvas.getContext('2d');
function drawNode() {
var s = {
x: (Math.random() * 200) + 50,
y: (Math.random() * 200) + 50
};
var paddingX = 6;
var paddingY = 6;
var contentWidth = s.x / 5;
var contentHeight = s.y / 5;
var boxWidth = contentWidth + paddingX;
var boxHeight = contentHeight + paddingY;
ctx.fillStyle = '#AAFFAA';
// I modified it so the whole canvas will be cleared
ctx.clearRect(0, 0, canvas.width, canvas.height);
// We start a new path
ctx.beginPath();
// then we draw our circle, setting its radius to the max between contentWidth and contentHeight
ctx.arc(s.x, s.y , Math.max(boxWidth,boxHeight)/2, 0, 2 * Math.PI);
// and finally we fill it
ctx.fill();
}
document.addEventListener('click', drawNode);
drawNode();

canvas{cursor:pointer};

<canvas height="300" width="300" />
&#13;
答案 1 :(得分:0)
我创建了一个简单的jsFiddle来展示如何绘制弯角矩形
- 已更新,因此您现在可以简单地更改roundedValue,然后更改角落的平滑度。
http://jsfiddle.net/gHCJt/1127/
// Get canvas
var canvas = $("#canvas");
var context = canvas.get(0).getContext("2d");
// Draw simple rect
var rectX = 125;
var rectY = 125;
var rectWidth = 150;
var rectHeight = 150;
var roundedValue = 75;
// Apply corner
context.lineJoin = "round";
context.lineWidth = roundedValue;
// Apply the corner to the draw method for strokeRect and fillRect
context.strokeRect(rectX+(roundedValue/2), rectY+(roundedValue/2), rectWidth-roundedValue, rectHeight-roundedValue);
context.fillRect(rectX+(roundedValue/2), rectY+(roundedValue/2), rectWidth-roundedValue, rectHeight-roundedValue);