Version 2.1.6

- Added `exposure()` filter.
- Added `lighting()` filter, with shadows and highlights.

README.md

@@ -897,6 +897,32 @@ This would *increase* the canvas size by 100px horizontally and vertically, esse
 
 Note that expanding regenerates the underlying canvas object.  It effectively creates a new canvas at the expanded size, then copies the source into the destination, then discards the source.
 
+### exposure
+
+**Live Demo:** [Exposure](https://jhuckaby.github.io/canvas-plus-playground/?t=load/eyJpbWFnZSI6ImtpdHRlbi5qcGcifQ%3D%3D&t=exposure/eyJhbW91bnQiOjI1fQ%3D%3D&f=png)
+
+The `exposure()` method simulates increasing or decreasing the camera film exposure.  Interally, this is accomplished by a special [curve](#curves).  To use, specify an `amount` between -100 (darken) and 100 (lighten).  The method accepts an object containing the following properties:
+
+| Property Name | Type | Description |
+|---------------|------|-------------|
+| `amount` | Integer | Exposure adjustment, from -100 (darken) to 100 (lighten). | 
+| `channels` | String | Which channels to apply the filter to, defaults to `rgb`.  See [Channels](#channels). |
+| `clip` | Object | Optional clipping rectangle (see [Clipping](#clipping) below). |
+
+Example use:
+
+```js
+canvas.exposure({
+	"amount": 25
+});
+```
+
+Note that if `amount` is the sole argument, you can simply pass the number itself:
+
+```js
+canvas.exposure( 25 );
+```
+
 ### findEdges
 
 **Live Demo:** [Find Edges](https://jhuckaby.github.io/canvas-plus-playground/?t=load/eyJpbWFnZSI6InN1bnNldC5qcGcifQ%3D%3D&t=resize/eyJ3aWR0aCI6NjQwLCJoZWlnaHQiOjQ4MCwibW9kZSI6ImZpdCJ9&t=findEdges/e30%3D&f=png)
@@ -1019,6 +1045,27 @@ canvas.curves({
 });
 ```
 
+### lighting
+
+**Live Demo:** [Shadow Detail](https://jhuckaby.github.io/canvas-plus-playground/?t=load/eyJpbWFnZSI6InN1bnNldC5qcGcifQ%3D%3D&t=lighting/eyJzaGFkb3dzIjo1MH0%3D&f=png)
+
+The `lighting()` method can adjust both shadows and highlights, to bring out hidden details.  Interally, this is accomplished by a special multi-point [curve](#curves).  The method accepts an object containing the following properties:
+
+| Property Name | Type | Description |
+|---------------|------|-------------|
+| `shadows` | Integer | Shadow detail adjustment, from -100 (darken) to 100 (lighten). | 
+| `highlights` | Integer | Highlight detail adjustment, from -100 (darken) to 100 (lighten). | 
+| `channels` | String | Which channels to apply the filter to, defaults to `rgb`.  See [Channels](#channels). |
+| `clip` | Object | Optional clipping rectangle (see [Clipping](#clipping) below). |
+
+Example use:
+
+```js
+canvas.lighting({
+	"shadows": 25
+});
+```
+
 ### mask
 
 **Live Demo:** [Apply Mask](https://jhuckaby.github.io/canvas-plus-playground/?t=load/eyJpbWFnZSI6IndhdGVyZmFsbC5qcGcifQ%3D%3D&t=resize/eyJ3aWR0aCI6NjQwLCJoZWlnaHQiOjQ4MCwibW9kZSI6ImZpdCJ9&t=mask/e30%3D&f=png)

canvas-plus.js

@@ -1554,6 +1554,83 @@ module.exports = Class.create({
 		return this.curves(opts);
 	},
 
+	lighting: function(opts) {
+		// apply lighting functions, e.g. shadows, highlights
+		// opts: { shadows, highlights, channels, clip }
+		opts = this.copyHash( opts || {} );
+		var curve = [ [0,0], [63,63], [191,191], [255,255] ];
+
+		// shadows
+		if (opts.shadows) {
+			curve[1][1] += opts.shadows;
+		}
+
+		// highlights
+		if (opts.highlights) {
+			curve[2][1] += opts.highlights;
+		}
+
+		for (var idx = 0, len = curve.length; idx < len; idx++) {
+			curve[idx][1] = Math.max(0, Math.min(255, curve[idx][1]) );
+		}
+
+		var channels = opts.channels || 'rgb';
+		delete opts.channels;
+
+		if (channels.match(/rgb/i)) opts.rgb = curve;
+		else {
+			if (channels.match(/r/i)) opts.red = curve;
+			if (channels.match(/g/i)) opts.green = curve;
+			if (channels.match(/b/i)) opts.blue = curve;
+		}
+		if (channels.match(/a/i)) opts.alpha = curve;
+
+		return this.curves(opts);
+	},
+
+	exposure: function(opts) {
+		// apply exposure adjustment
+		// opts: { amount, channels, clip }
+		if (typeof(opts) == 'number') {
+			opts = { amount: opts };
+		}
+		opts = this.copyHash( opts || {} );
+		var curve = [ 0, 63, 127, 191, 255 ];
+
+		// exposure
+		if (opts.amount) {
+			if (opts.amount > 0) {
+				curve[1] += (opts.amount * 2);
+				curve[2] += (opts.amount * 3);
+				curve[3] += (opts.amount * 4);
+			}
+			else {
+				opts.amount /= 2;
+				curve[4] += (opts.amount * 5);
+				curve[3] += (opts.amount * 4);
+				curve[2] += (opts.amount * 3);
+				curve[1] += (opts.amount * 2);
+			}
+		}
+
+		for (var idx = 0, len = curve.length; idx < len; idx++) {
+			curve[idx] = Math.max(0, Math.min(255, curve[idx]) );
+		}
+
+		var channels = opts.channels || 'rgb';
+		delete opts.channels;
+
+		if (channels.match(/rgb/i)) opts.rgb = curve;
+		else {
+			if (channels.match(/r/i)) opts.red = curve;
+			if (channels.match(/g/i)) opts.green = curve;
+			if (channels.match(/b/i)) opts.blue = curve;
+		}
+		if (channels.match(/a/i)) opts.alpha = curve;
+
+		return this.curves(opts);
+	},
+
 	generateCurve: function(points) {
 		// Generate curve from points using monotone cubic interpolation.
 		// This is somewhat like Adobe Photoshop's 'Curves' filter.
@@ -3765,7 +3842,7 @@ module.exports = Class.create({
 			this.logDebug(6, "Compressing into WebP format", opts );
 
 			this.webp.encode( imgData, opts, function(err, data) {
-				if (err) return doError('webp', "WebP Encode Error: " + err, callback);
+				if (err) return self.doError('webp', "WebP Encode Error: " + err, callback);
 				self.logDebug(6, "WebP compression complete");
 				callback(null, data);
 			} );

lib/filter/curves.js

@@ -302,6 +302,83 @@ module.exports = Class.create({
 		return this.curves(opts);
 	},
 
+	lighting: function(opts) {
+		// apply lighting functions, e.g. shadows, highlights
+		// opts: { shadows, highlights, channels, clip }
+		opts = this.copyHash( opts || {} );
+		var curve = [ [0,0], [63,63], [191,191], [255,255] ];
+
+		// shadows
+		if (opts.shadows) {
+			curve[1][1] += opts.shadows;
+		}
+
+		// highlights
+		if (opts.highlights) {
+			curve[2][1] += opts.highlights;
+		}
+
+		for (var idx = 0, len = curve.length; idx < len; idx++) {
+			curve[idx][1] = Math.max(0, Math.min(255, curve[idx][1]) );
+		}
+
+		var channels = opts.channels || 'rgb';
+		delete opts.channels;
+
+		if (channels.match(/rgb/i)) opts.rgb = curve;
+		else {
+			if (channels.match(/r/i)) opts.red = curve;
+			if (channels.match(/g/i)) opts.green = curve;
+			if (channels.match(/b/i)) opts.blue = curve;
+		}
+		if (channels.match(/a/i)) opts.alpha = curve;
+
+		return this.curves(opts);
+	},
+
+	exposure: function(opts) {
+		// apply exposure adjustment
+		// opts: { amount, channels, clip }
+		if (typeof(opts) == 'number') {
+			opts = { amount: opts };
+		}
+		opts = this.copyHash( opts || {} );
+		var curve = [ 0, 63, 127, 191, 255 ];
+
+		// exposure
+		if (opts.amount) {
+			if (opts.amount > 0) {
+				curve[1] += (opts.amount * 2);
+				curve[2] += (opts.amount * 3);
+				curve[3] += (opts.amount * 4);
+			}
+			else {
+				opts.amount /= 2;
+				curve[4] += (opts.amount * 5);
+				curve[3] += (opts.amount * 4);
+				curve[2] += (opts.amount * 3);
+				curve[1] += (opts.amount * 2);
+			}
+		}
+
+		for (var idx = 0, len = curve.length; idx < len; idx++) {
+			curve[idx] = Math.max(0, Math.min(255, curve[idx]) );
+		}
+
+		var channels = opts.channels || 'rgb';
+		delete opts.channels;
+
+		if (channels.match(/rgb/i)) opts.rgb = curve;
+		else {
+			if (channels.match(/r/i)) opts.red = curve;
+			if (channels.match(/g/i)) opts.green = curve;
+			if (channels.match(/b/i)) opts.blue = curve;
+		}
+		if (channels.match(/a/i)) opts.alpha = curve;
+
+		return this.curves(opts);
+	},
+
 	generateCurve: function(points) {
 		// Generate curve from points using monotone cubic interpolation.
 		// This is somewhat like Adobe Photoshop's 'Curves' filter.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "pixl-canvas-plus",
-  "version": "2.1.5",
+  "version": "2.1.6",
   "description": "A universal library for manipulating images, built on canvas.",
   "author": "Joseph Huckaby <jhuckaby@gmail.com>",
   "homepage": "https://github.com/jhuckaby/canvas-plus",