jimp-dev/jimp

"print" method on transparent background produces black fringe

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#652 opened on Oct 28, 2018

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Description

Expected Behavior

Printing text on a image with a transparent background should result in text with a transparent fringe.

Current Behavior

Instead of a transparent fringe, the text is drawn with a black fringe.

Possible Fix

In the drawCharacter method of plugin-print, changing:

image.blit(characterPage, x + char.xoffset, y + char.yoffset, char.x, char.y, char.width, char.height);

...to:

image.composite(characterPage.clone().crop(char.x, char.y, char.width, char.height), x + char.xoffset, y + char.yoffset);

...seems to "fix" the fringe. There may be a more efficient way to do it though!

Contributor guide

Research direction
Investigate the difference between image.blit and image.composite in the library. Test the drawCharacter method in plugin print with a transparent background to understand why composite fixes the black fringe.
Tech stack
javascriptnodejs
Domain
backend
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
JavaScriptGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75