我想在程序中使用相同的var rectangle
绘制矩形和方形。我已经修改了绘制方形的函数,给定modeOptions = { "Rectangle", "Square" }
下面需要添加的内容,以适用于矩形和方形。请建议。感谢
还可以在http://jsfiddle.net/farey/qP3kV/6/
上看到问题var rectangle=(function() {
var inDrag=false,downPos,upPos;
var obj;
// temporary length for square
var temp;
return {
fillStyle: "none",
strokeStyle: "blue",
lineWidth: 5,
construct: function(pos,parent) {
obj=Object.create(parent);
obj.minx=obj.maxx=pos.x;
obj.miny=obj.maxy=pos.y;
if (fillColor!="inherit")
obj.fillStyle=fillColor;
if (strokeColor!="inherit")
obj.strokeStyle=strokeColor;
if (strokeThickness!="inherit")
obj.lineWidth=strokeThickness;
},
draw: function(selected) {
ctx.beginPath();
ctx.fillStyle=this.fillStyle;
ctx.strokeStyle=(selected) ?
"gray" : this.strokeStyle;
ctx.lineWidth=this.lineWidth;
// making 3rd & fourth argument same for square. greater of maxx and maxy should be there
if (this.maxx - this.minx > this.maxy - this.miny)
{ temp = this.maxx - this.minx
}
else
temp = this.maxy - this.miny
ctx.rect(this.minx,this.miny,temp,temp);
// else
// ctx.rect(this.minx,this.miny,this.maxx - this.minx,this.maxy - this.miny )
ctx.fill();
if (selected) {
ctx.moveTo(this.minx,this.miny);
ctx.lineTo(this.maxx,this.maxy);
ctx.moveTo(this.minx,this.maxy);
ctx.lineTo(this.maxx,this.miny);
}
ctx.stroke();
},
mousedown: function(event) {
downPos=event;
rectangle.construct(downPos,drawObject[containingBox4point(downPos)]);
inDrag=true;
},
mousemove: function(event) {
if (!inDrag)
{
drawPrevious();
drawCursor(event,containingBox4point(event));
return;
}
upPos=event;
if (upPos.x>downPos.x) {
obj.minx=downPos.x;
obj.maxx=upPos.x;
}
else {
obj.minx=upPos.x;
obj.maxx=downPos.x;
}
if (upPos.y>downPos.y) {
obj.miny=downPos.y;
obj.maxy=upPos.y;
}
else {
obj.miny=upPos.y;
obj.maxy=downPos.y;
}
drawPrevious();
obj.draw(containingBox(obj)==(-1));
drawCursor(event,containingBox4point(upPos));
},
mouseup: function(event) {
// commit rectangle
rectangle.mousemove(event);
if (!inDrag)
return;
if (containingBox(obj)==(-1))
trace("U and ur box are evil . . .");
else
{
drawObject.push(obj);
trace("Rectangle props for new box "+String(drawObject.length-1)+
": filled with "+ fillColor+
" stroked with "+strokeColor+
" @ thickness "+ strokeThickness);
}
inDrag=false;
drawPrevious();
},
mouseout: function(event) {
inDrag=false;
drawPrevious();
}
};
})(); // rectangle
答案 0 :(得分:0)
要强制生成的矩形只是一个正方形,您需要修改矩形mousemove方法。
修改将强制执行此操作:
Math.abs(obj.maxx-obj.minx) == Math.abs(obj.maxy-obj.miny).
由您决定如何强制执行该结果。
例如,假设upPos是从downPos向右和向下:
你可以让水平长度获胜:
obj.maxy = obj.miny+(obj.maxx-obj.minx);
你可以让垂直长度获胜:
obj.maxx = obj.minx+(obj.maxy-obj.miny);
你甚至可以让minx / miny浮动来创建一个正方形:
obj.minx = obj.maxx – (obj.maxy-obj.miny);
// or
obj.miny= obj.maxy – (obj.maxx-obj.minx);