CommunityToolkit/WindowsCommunityToolkit

ImageCropper creates artifacts when switching between images

Open

#3,708 opened on Jan 30, 2021

View on GitHub
 (4 comments) (0 reactions) (0 assignees)C# (1,403 forks)batch import
bug :bug:help wantedquestion :grey_question:

Repository metrics

Stars
 (5,708 stars)
PR merge metrics
 (No merged PRs in 30d)

Description

I am using ImageCropper in an app that allows the user to crop multiple bitmaps before submitting the changes in one batch. The user needs to switch between bitmaps.

I let her select bitmaps through a ListView. Every time the ListView has a new SelectedItem, I grab the current CroppedRegion off the ImageCropper and store it with the bitmap instance. Then I load the newly selected bitmap into ImageCropper and try to set the cropped rect. The bitmap initializes the stored Crop to 0/0/Width/Height...

When switching between bitmaps I notice that the ImageCropper produces wrong crop rectangles and sometimes even artifacts of underlying canvas pixels... Do I need to wait for the load and process to finish???

Anything I am not getting?

Maybe it would be a good idea to make two changes:

  1. Give LoadImageFromFile() an optional parameter Rect? that identifies a desired cropped region
  2. Raise an event every time the user changes the Crop so that the app can track changes by the user

This was posted as a bug in https://github.com/MicrosoftDocs/WindowsCommunityToolkitDocs/issues/400 and was suggested to be posted here as well...

Contributor guide

Research direction
Inspect the ImageCropper control's internal state handling when loading a new image. Ensure that the previous cropped region and canvas artifacts are cleared before setting the new crop rectangle. Consider adding a callback or event for crop changes.
Tech stack
csharp
Domain
desktop
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C#Windows Development
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70