68 lines
1.4 KiB
Markdown
68 lines
1.4 KiB
Markdown
<div align="center">
|
|
<img width="200" height="200"
|
|
src="https://s3.amazonaws.com/pix.iemoji.com/images/emoji/apple/ios-11/256/crayon.png">
|
|
<h1>@jimp/utils</h1>
|
|
<p>Utils for jimp extensions.</p>
|
|
</div>
|
|
|
|
## Available Methods
|
|
|
|
### isNodePattern
|
|
|
|
Determines if function was passed an node callback.
|
|
|
|
```js
|
|
if (isNodePattern(cb)) {
|
|
cb.call(this, null, this);
|
|
}
|
|
```
|
|
|
|
### throwError
|
|
|
|
Either throws the error or calls the callback with the error.
|
|
|
|
```js
|
|
if (/* check for error */) {
|
|
return throwError.call(this, 'someError', cb);
|
|
}
|
|
```
|
|
|
|
### scan
|
|
|
|
Scans through a region of the bitmap, calling a function for each pixel.
|
|
|
|
```js
|
|
function removeRed(image) {
|
|
return scan(image, 0, 0, image.bitmap.width, image.bitmap.height, function(
|
|
x,
|
|
y,
|
|
index
|
|
) {
|
|
const red = this.bitmap.data[index + 0];
|
|
const green = this.bitmap.data[index + 1];
|
|
const blue = this.bitmap.data[index + 2];
|
|
const alpha = this.bitmap.data[index + 3];
|
|
|
|
this.bitmap.data[index + 0] = 0;
|
|
this.bitmap.data[index + 1] = green;
|
|
this.bitmap.data[index + 2] = blue;
|
|
this.bitmap.data[index + 3] = alpha;
|
|
});
|
|
}
|
|
```
|
|
|
|
### scanIterator
|
|
|
|
It's possible to make an iterator scan with a `for ... of`, if you want to `break` the scan before it reaches the end, but note, that this iterator has a huge performance implication:
|
|
|
|
```js
|
|
for (const { x, y, idx, image } of scanIterator(
|
|
image,
|
|
0,
|
|
0,
|
|
image.bitmap.width,
|
|
image.bitmap.height
|
|
)) {
|
|
}
|
|
```
|