Treat a saved canvas transform as a snapshot
A matrix returned by ctx.getTransform() is a snapshot. Later changes to the context do not update that object, and changing the object does not update the context. Suppose a preview stores its transfo
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Set image smoothing before drawing a scaled canvas image
Set ctx.imageSmoothingEnabled before you call drawImage(). To compare a different setting, draw the image again; the assignment does not change pixels already drawn. The default is true. For a pixel-a
Give each image upload attempt its own AbortController
Make image-upload cancellation belong to one attempt. A new attempt needs a fresh controller and a cancel control that still points to it. Keep the controller with the job identifier. When the user ca
Wait for the upload response before saying an image was accepted
Wait for the server response before displaying image accepted. Upload progress describes the request body transfer, so keep its completion separate from the application result. Use progress informatio
Close an ImageBitmap when its drawing work is finished
Close an ImageBitmap after the work that needs it has finished. Tie that cleanup to the bitmap's owner and account for drawing failures as well as success. For a bitmap used only for one canvas draw,
Handle image decode rejection before replacing the preview
Put the preview replacement after a successful await of image.decode(). Keep a catch branch for decoding failure so the page does not report success for an unusable image. A small sequence is: create
Check the encoded type before naming a canvas export
Choose a canvas export's filename after checking the produced format. toBlob() exports PNG when the requested type is unsupported; naming only from the request can give that output the wrong extension
Ignore an older image job when a newer one owns the result panel
Check which image job owns the result panel before updating it. If the panel follows the latest started job, an earlier job must not overwrite it when it finishes later. Capture a sequence value at jo
Snapshot the file selection before starting a batch
Accept a file selection into its own array before starting image-batch work. The input exposes a FileList; the array gives later work a list belonging to the accepted batch. function takeSelection(inp