Javascript 如何通过拖动角来调整html5画布元素的大小,并且应该保持纵横比?
这非常适合调整大小,但我还必须在从左上角、右上角、左下角和右下角拖动时保持纵横比 [应按角点调整大小,并应保持纵横比][1]Javascript 如何通过拖动角来调整html5画布元素的大小,并且应该保持纵横比?,javascript,canvas,html5-canvas,image-resizing,aspect-ratio,Javascript,Canvas,Html5 Canvas,Image Resizing,Aspect Ratio,这非常适合调整大小,但我还必须在从左上角、右上角、左下角和右下角拖动时保持纵横比 [应按角点调整大小,并应保持纵横比][1] const canvas = CanvasData.canvas.getBoundingClientRect(); if (selectedShape === "TopLeft") { mousePos = point(e.pageX - canvas.left, e.pageY - canvas.top);
const canvas = CanvasData.canvas.getBoundingClientRect();
if (selectedShape === "TopLeft") {
mousePos = point(e.pageX - canvas.left, e.pageY - canvas.top);
CanvasData.activeObject.width = CanvasData.activeObject.width + CanvasData.activeObject.x - mousePos.x
CanvasData.activeObject.height = CanvasData.activeObject.height + CanvasData.activeObject.y - mousePos.y
CanvasData.activeObject.x = mousePos.x;
CanvasData.activeObject.y = mousePos.y;
} else if (selectedShape === "TopCenter") {
mousePos = point(e.pageX - canvas.left, e.pageY - canvas.top);
CanvasData.activeObject.height += CanvasData.activeObject.y - mousePos.y;
CanvasData.activeObject.y = mousePos.y;
} else if (selectedShape === "TopRight") {
CanvasData.activeObject.width = mousePos.x - CanvasData.activeObject.x;
CanvasData.activeObject.height += CanvasData.activeObject.y - mousePos.y;
CanvasData.activeObject.y = mousePos.y;
} else if (selectedShape === "LeftCenter") {
mousePos = point(e.pageX - canvas.left, e.pageY - canvas.top);
CanvasData.activeObject.width += CanvasData.activeObject.x - mousePos.x;
CanvasData.activeObject.x = mousePos.x;
} else if (selectedShape === "BottomLeft") {
mousePos = point(e.pageX - canvas.left, e.pageY - canvas.top);
CanvasData.activeObject.width += CanvasData.activeObject.x - mousePos.x;
CanvasData.activeObject.x = mousePos.x;
CanvasData.activeObject.height = mousePos.y - CanvasData.activeObject.y;
} else if (selectedShape === "BottomCenter") {
mousePos = point(e.pageX - canvas.left, e.pageY - canvas.top);
CanvasData.activeObject.height = mousePos.y - CanvasData.activeObject.y;
} else if (selectedShape === "BottomRight") {
mousePos = point(e.pageX - canvas.left, e.pageY - canvas.top);
CanvasData.activeObject.width = mousePos.x - CanvasData.activeObject.x;
CanvasData.activeObject.height = mousePos.y - CanvasData.activeObject.y;
} else if (selectedShape === "RightCenter") {
mousePos = point(e.pageX - canvas.left, e.pageY - canvas.top);
CanvasData.activeObject.width = mousePos.x - CanvasData.activeObject.x;
}
}```
[1]: https://i.stack.imgur.com/kP9pP.png