Overview
Introduction
This tool erases a rectangular region of a PNG by making it fully transparent, entirely in your browser.
It works on a plain pixel buffer, so nothing you upload is sent to a server.
What Is PNG Area Eraser?
A precise rectangular erase tool: you specify a region by pixel coordinates and dimensions, and every pixel inside that rectangle gets its alpha channel zeroed out.
Unlike the censorer (which pixelates the whole image) or the chroma key remover (which targets a color), this tool erases an exact, arbitrary rectangle you define numerically.
How PNG Area Eraser Works
You provide the erase rectangle's top-left x/y coordinates plus its width and height, all in pixels.
The tool clones the image, then for every pixel whose coordinates fall inside that rectangle (clamped to the image bounds), it sets that pixel's alpha channel to 0, leaving its RGB values untouched but invisible.
When To Use PNG Area Eraser
Use it when you know the exact pixel region you want to remove, like a watermark in a known corner, a UI element in a screenshot, or a specific object at known coordinates.
It's a precise, numeric alternative to a freehand eraser tool when you need repeatable, exact results.
Often used alongside PNG Censorer, PNG Opacifier and Transparent PNG Areas Highlighter.
Features
Advantages
- Runs entirely client-side; nothing you upload leaves your device.
- Exact, repeatable erasing driven by numeric coordinates rather than freehand drawing.
- Automatically clamps an out-of-bounds region instead of failing outright.
Limitations
- Only rectangular regions are supported; there's no freehand or irregular-shape erasing.
- You need to know (or determine, e.g. from the dimensions finder tool) the exact pixel coordinates in advance, since there's no interactive click-and-drag selection.
Examples
Best Practices & Notes
Best Practices
- Use the PNG Dimensions Finder tool first if you need to confirm the image's exact pixel size before calculating your erase coordinates.
- Double-check your x/y/width/height values against the image preview before downloading.
Developer Notes
The lib function validates that all four inputs are whole numbers and that the region's top-left corner falls within the image, then clamps the erase loop's end bounds to the image's actual width/height so an oversized region degrades gracefully instead of erroring.
PNG Area Eraser Use Cases
- Removing a watermark or logo from a known screen position
- Clearing out a UI element from a screenshot before sharing it
- Blanking a specific region of a template image before customizing it
Common Mistakes
- Assuming out-of-bounds coordinates will error the same way an out-of-bounds starting corner does — only the width/height overflow is clamped, not an out-of-bounds x/y.
- Forgetting that erased pixels stay in the file with their RGB data intact, just invisible; the file size doesn't necessarily shrink much.
Tips
- Use the dimensions finder or upload preview to read off exact pixel coordinates before erasing.
- Combine with the corner rounder or border adder afterward if the erased region needs a decorative treatment instead of plain transparency.