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Allow embed with rgba background #86 #89

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Small memory leak mop-up related to #94
This commit is contained in:
Lovell Fuller
2014-10-02 20:02:14 +01:00
parent 5cdfbba55c
commit 0cba506bc4
6 changed files with 242 additions and 199 deletions
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61
README.md
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@@ -180,7 +180,8 @@ http.createServer(function(request, response) {
sharp(inputBuffer)
.resize(200, 300)
.interpolateWith(sharp.interpolator.nohalo)
.embedWhite()
.background('white')
.embed()
.toFile('output.tiff')
.then(function() {
// output.tiff is a 200 pixels wide and 300 pixels high image
@@ -190,20 +191,29 @@ sharp(inputBuffer)
```
```javascript
sharp('input.gif').resize(200, 300).embedBlack().webp().toBuffer(function(err, outputBuffer) {
if (err) {
throw err;
}
// outputBuffer contains WebP image data of a 200 pixels wide and 300 pixels high
// containing a scaled version, embedded on a black canvas, of input.gif
});
sharp('input.gif')
.resize(200, 300)
.background({r: 0, g: 0, b: 0, a: 0})
.embed()
.webp()
.toBuffer(function(err, outputBuffer) {
if (err) {
throw err;
}
// outputBuffer contains WebP image data of a 200 pixels wide and 300 pixels high
// containing a scaled version, embedded on a transparent canvas, of input.gif
});
```
```javascript
sharp(inputBuffer).resize(200, 200).max().jpeg().toBuffer().then(function(outputBuffer) {
// outputBuffer contains JPEG image data no wider than 200 pixels and no higher
// than 200 pixels regardless of the inputBuffer image dimensions
});
sharp(inputBuffer)
.resize(200, 200)
.max()
.jpeg()
.toBuffer().then(function(outputBuffer) {
// outputBuffer contains JPEG image data no wider than 200 pixels and no higher
// than 200 pixels regardless of the inputBuffer image dimensions
});
```
## API
@@ -234,6 +244,7 @@ Fast access to image metadata without decoding any compressed image data.
* `height`: Number of pixels high
* `space`: Name of colour space interpretation e.g. `srgb`, `rgb`, `scrgb`, `cmyk`, `lab`, `xyz`, `b-w` [...](https://github.com/jcupitt/libvips/blob/master/libvips/iofuncs/enumtypes.c#L502)
* `channels`: Number of bands e.g. `3` for sRGB, `4` for CMYK
* `hasAlpha`: Boolean indicating the presence of an alpha transparency channel
* `orientation`: Number value of the EXIF Orientation header, if present
A Promises/A+ promise is returned when `callback` is not provided.
@@ -244,10 +255,6 @@ An advanced setting that switches the libvips access method to `VIPS_ACCESS_SEQU
### Image transformation options
#### background(color) or background(r, g, b)
Set background color for operations such as `flatten`. Pass any valid CSS color as `color` string, e.g. `'#00ff00'`, `'hsl(120,100%,50%)'`, etc., or as numbers in the range of `[0, 255]` for `r`, `g`, and `b`. Defaults color to black.
#### resize(width, [height])
Scale output to `width` x `height`. By default, the resized image is cropped to the exact size specified.
@@ -266,21 +273,29 @@ Possible values are `north`, `east`, `south`, `west`, `center` and `centre`. The
#### max()
Preserving aspect ratio, resize the image to the maximum width or height specified.
Preserving aspect ratio, resize the image to the maximum `width` or `height` specified.
Both `width` and `height` must be provided via `resize` otherwise the behaviour will default to `crop`.
#### embedWhite()
#### background(rgba)
Embed the resized image on a white background of the exact size specified.
Set the background for the `embed` and `flatten` operations.
#### embedBlack()
`rgba` is parsed by the [color](https://www.npmjs.org/package/color) module to extract values for red, green, blue and alpha.
Embed the resized image on a black background of the exact size specified.
The alpha value is a float between `0` (transparent) and `1` (opaque).
The default background is `{r: 0, g: 0, b: 0, a: 1}`, black without transparency.
#### embed()
Preserving aspect ratio, resize the image to the maximum `width` or `height` specified then embed on a background of the exact `width` and `height` specified.
If the background contains an alpha value then WebP and PNG format output images will contain an alpha channel, even when the input image does not.
#### flatten()
Flatten transparent images onto background with a color set using `background`.
Merge alpha transparency channel, if any, with `background`.
#### rotate([angle])
@@ -327,7 +342,7 @@ JPEG input images will not take advantage of the shrink-on-load performance opti
Convert to 8-bit greyscale; 256 shades of grey.
This is a linear operation. If the input image is in a non-linear colourspace such as sRGB, use `gamma()` with `greyscale()` for the best results.
This is a linear operation. If the input image is in a non-linear colour space such as sRGB, use `gamma()` with `greyscale()` for the best results.
The output image will still be web-friendly sRGB and contain three (identical) channels.