嗨,我想在我的项目中使用自定义定义颜色,而不是使用随机颜色,因为其中某些颜色在我的背景中不可见。我的背景不是白色,该如何实现。
我想创建一个下拉菜单,从中可以选择颜色并绘制图层,也可以在randomcolors函数中自定义定义颜色。
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
var canvasOffset = $("#canvas").offset();
var offsetX = canvasOffset.left;
var offsetY = canvasOffset.top;
var isDown = false;
var startY;
var layers = [];
var currentColor = "black";
function handleMouseDown(e) {
e.preventDefault();
startX = parseInt(e.clientX - offsetX);
startY = parseInt(e.clientY - offsetY);
currentColor = randomColor();
isDown = true;
}
function handleMouseUp(e) {
e.preventDefault();
mouseX = parseInt(e.clientX - offsetX);
mouseY = parseInt(e.clientY - offsetY);
isDown = false;
layers.push({
y1: startY,
y2: mouseY,
color: currentColor
});
}
function handleMouseOut(e) {
e.preventDefault();
mouseX = parseInt(e.clientX - offsetX);
mouseY = parseInt(e.clientY - offsetY);
isDown = false;
layers.push({
y1: startY,
y2: mouseY,
color: currentColor
});
}
function handleMouseMove(e) {
if (!isDown) {
return;
}
e.preventDefault();
mouseX = parseInt(e.clientX - offsetX);
mouseY = parseInt(e.clientY - offsetY);
drawAll();
hLine(startY, currentColor);
hLine(mouseY, currentColor);
}
function drawAll() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
for (var i = 0; i < layers.length; i++) {
layer = layers[i];
hLine(layer.y1, layer.color);
hLine(layer.y2, layer.color);
}
}
function hLine(y, color) {
ctx.beginPath();
ctx.moveTo(0, y);
ctx.lineTo(canvas.width, y);
ctx.strokeStyle = color;
ctx.stroke();
}
function randomColor() {
return ('#' + Math.floor(Math.random() * 16777215).toString(16));
}
$("#canvas").mousedown(function (e) {
handleMouseDown(e);
});
$("#canvas").mousemove(function (e) {
handleMouseMove(e);
});
$("#canvas").mouseup(function (e) {
handleMouseUp(e);
});
$("#canvas").mouseout(function (e) {
handleMouseOut(e);
});
只需为创建一个输入select
,然后通过使用该值即可jQuery
。
<select id="pickCol">
<option value="#FF0000">Red</option>
<option value="#0000FF">Blue</option>
<option value="#00FF00">Green</option>
</select>
和JS:
currentColor = $("#pickCol").val();
本文收集自互联网,转载请注明来源。
如有侵权,请联系 [email protected] 删除。
我来说两句