picha - npm Package Compare versions

Comparing version 0.2.0 to 0.3.0

lib/image.js

@@ -74,1 +74,9 @@
 }
+
+Image.prototype.copy = function(targetImage) {
+	if (targetImage.pixel != this.pixel)
+		throw new Error("can't copy pixels between different pixel types");
+	var rw = this.pixelSize() * Math.min(this.width, targetImage.width);
+	var h = Math.min(this.height, targetImage.height);
+	for (var y = 0; y < h; ++y)		this.data.copy(targetImage.data, y * targetImage.stride, y * this.stride, y * this.stride + rw);
+}

package.json

 {
   "name": "picha",
-  "version": "0.2.0",
+  "version": "0.3.0",
   "description": "image format codec and simple image processing",
@@ -5,0 +5,0 @@ "main": "index.js",

README.md

@@ -9,4 +9,111 @@ picha
 
+## Usage
+```
+var fs = require('fs');
+var picha = require('picha');
+
+var image = picha.decodeSync(fs.readFileSync("test.jpeg"));
+var resized = picha.resizeSync(image, { width: 100, height: 100 });
+var cropped = resized.subView(20, 20, 60, 60);
+var compressed = picha.encodePngSync(cropped);
+fs.writeFileSync('tested.png', compressed);
+```
+
+## API
+
+### Image
+### `new picha.Image(opt)`
+Construct a new image object from the options opt
+* opt.width: width of the image in pixels
+* opt.height: height of the image in pixels
+* opt.pixel: pixel format (rgb, rgba, grey, greya)
+* opt.stride: row stride in bytes - defaults to 4 byte aligned rows
+* opt.data: buffer of data
+
+If the data buffer isn't provided an appropriate buffer will be allocated.
+
+### `Image.subView(x, y, w, h)`
+Return a new image that is a rectangulare view into this image defined by the supplied pixel coordinates.
+
+### `Image.copy(targetImage)`
+Copy the pixels from this image to the target Image. The pixel format must match.
+If the sizes don't match then overlapping or missing pixels are discarded.
+
+### `Image.pixelSize()`
+The size, in bytes, of this images pixel format.
+
+### `Image.row(y)`
+Return a slice of buffer for a row of the image.
+
+### `Image.equalPixels(o)`
+Return true if this image and another image 'o' are pixel for pixel equal.
+
+### `Image.avgChannelDiff(o)`
+Return the average channel by channel difference between this and another image 'o'.
+
+### Image codec
+
+### `picha.stat(buf)`
+Decode the image header and grab the image vitals. Only yhe first handful of bytes of the
+image data is required. The function returns null or
+```
+{
+    width: the width of the image
+    height: the height of the image
+    pixel: pixel format
+    mimetype: one of "image/jpeg" or "image/png"
+}
+```
+
+### `picha.decode(buf, cb)`
+Decodes the supplied image data on a libuv thread and calls cb with (err, image).
+
+### `picha.decodeSync(buf)`
+Decodes the supplied image data on the v8 thread and returns the image.
+
+### `picha.encodePng(image, cb)`
+Encode the supplied image into png format on a libuv thread. The cb receives (err, buffer).
+
+### `picha.encodeJpeg(image, opt, cb)`
+Encode the supplied image into jpeg format on a libuv thread. The cb receives (err, buffer).
+The optional opt object may specify { quality: 85 }.
+
+### `picha.statPng(buf)`
+### `picha.statJpeg(buf)`
+Decode the header of the respective image formats and returns null or an object containing the
+width, height and pixel format.
+
+### `picha.decodePng(buf, cb)`
+### `picha.decodeJpeg(buf, cb)`
+Decode the respective image format data on a libuv thread and call cb with (err, image).
+
+### `picha.decodePngSync(buf)`
+### `picha.decodeJpegSync(buf)`
+Decode the respective image format data on the v8 thread and return the image.
+
+### Image manipulation
+
+### `picha.resize(image, opt, cb)`
+Resize the image with the provided options. The computation is performed on a libuv thread and cb receives (err, image).
+* opt.width: the width to resize
+* opt.height: the height to resize
+* opt.filter: optional resize filter - cubic (default), lanczos, catmulrom, mitchel, box, or triangle.
+* opt.filterScale: optional scale to apply to the filter (0.70)
+
+### `picha.resizeSync(image, opt)`
+Resize an image on the v8 thread. The resize image is returned.
+
+### `picha.colorConvert(image, opt, cb)`
+Convert the color format of the image. The computation is on the a libuv thread and cb receives (err, image).
+* opt.pixel: the pixel format to convert to (rgb, rgba, grey, greya)
+* opt.redWeight: optional weight of the red channel for rgb->grey conversion (0.299)
+* opt.greenWeight: optional weight of the green channel for rgb->grey conversion (0.587)
+* opt.blueWeight: optional weight of the blue channel for rgb->grey conversion (0.114)
+
+### `picha.colorConvertSync(image, opt)`
+Convert the color format of the image. The computation is on the v8 thread and the resulting image is returned.
+
+
 ## License
 
   MIT

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Improved metrics

Total package byte prevSize

82679

increased by6.7%

Number of package files

28

increased by3.7%

Lines of code

411

increased by5.66%

Number of lines in readme file

119

increased by891.67%

Worsened metrics

Number of low supply chain risk alerts

6

increased by20%

No dependency changes