I wrote a paint application using the HTML5 canvas element.
Now I want to give the user an option to zoom in and out while painting.
How can I do this?
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I wrote a paint application using the HTML5 canvas element.
Now I want to give the user an option to zoom in and out while painting.
How can I do this?
There are a few ways. It really depends on what you’re looking for.
You could do it by scaling the entire context, as in
ctx.scale(2,2), and then redrawing everything at this larger scale. Several things drawn, like paths and text, will scale gracefully. To accomplish this you will need to keep good track of everything drawn so far.Another way is to take the entire canvas and draw it back to itself. This requires a temporary canvas because the operation is really: Draw to temp canvas, clear main, draw back to main scaled.
Another way is to use CSS transforms to merely zoom the canvas itself, which will make the image blurry (its zoomed!) but does not require changing any of the pixels already on the canvas.