add advanced blit

Author: oliver-moran

README.md

@@ -79,7 +79,8 @@ image.opacity( f );            // multiply the alpha channel by each pixel by th
 image.resize( w, h );          // resize the image. Jimp.AUTO can be passed as one of the values.
 image.scale( f );              // scale the image by the factor f
 image.rotate( deg[, resize] ); // rotate the image clockwise by a number of degrees. Unless `false` is passed as the second parameter, the image width and height will be resized appropriately.
-image.blit( src, x, y );       // blit the image with another Jimp image at x, y
+image.blit( src, x, y[, srcx, srcy, srcw, srch] );
+                               // blit the image with another Jimp image at x, y, optionally cropped.
 image.composite( src, x, y );  // composites another Jimp image over this iamge at x, y
 image.brightness( val );       // adjust the brighness by a value -1 to +1
 image.contrast( val );         // adjust the contrast by a value -1 to +1

index.js

@@ -829,22 +829,48 @@ Jimp.prototype.autocrop = function (cb) {
  * @param src the source Jimp instance
  * @param x the x position to blit the image
  * @param y the y position to blit the image
+ * @param srcx (optional) the x position from which to crop the source image
+ * @param srcy (optional) the y position from which to crop the source image
+ * @param srcw (optional) the width to which to crop the source image
+ * @param srch (optional) the height to which to crop the source image
  * @param (optional) cb a callback for when complete
  * @returns this for chaining of methods
 */
-Jimp.prototype.blit = function (src, x, y, cb) {
+Jimp.prototype.blit = function (src, x, y, srcx, srcy, srcw, srch, cb) {
     if ("object" != typeof src || src.constructor != Jimp)
         return throwError.call(this, "The source must be a Jimp image", cb);
     if ("number" != typeof x || "number" != typeof y)
         return throwError.call(this, "x and y must be numbers", cb);
 
+    if ("function" == typeof srcx) {
+        cb = srcx;
+        srcx = 0;
+        srcy = 0;
+        srcw = src.bitmap.width;
+        srch = src.bitmap.height;
+    } else if (typeof srcx == typeof srcy && typeof srcy == typeof srcw && typeof srcw == typeof srch) {
+        srcx = srcx || 0;
+        srcy = srcy || 0;
+        srcw = srcw || src.bitmap.width;
+        srch = srch || src.bitmap.height;
+    } else {
+        return throwError.call(this, "srcx, srcy, srcw, srch must be numbers", cb);
+    }
+
+
     // round input
     x = Math.round(x);
     y = Math.round(y);
 
+    // round input
+    srcx = Math.round(srcx);
+    srcy = Math.round(srcy);
+    srcw = Math.round(srcw);
+    srch = Math.round(srch);
+
     var that = this;
-    src.scan(0, 0, src.bitmap.width, src.bitmap.height, function(sx, sy, idx) {
-        var dstIdx = that.getPixelIndex(x+sx, y+sy);
+    src.scan(srcx, srcy, srcw, srch, function(sx, sy, idx) {
+        var dstIdx = that.getPixelIndex(x+sx-srcx, y+sy-srcy);
         that.bitmap.data[dstIdx] = this.bitmap.data[idx];
         that.bitmap.data[dstIdx+1] = this.bitmap.data[idx+1];
         that.bitmap.data[dstIdx+2] = this.bitmap.data[idx+2];

test/blit.js

@@ -0,0 +1,15 @@
+var Jimp = require("../index.js");
+
+var p1 = Jimp.read("lenna.png");
+var p2 = Jimp.read("https://upload.wikimedia.org/wikipedia/commons/0/01/Bot-Test.jpg");
+
+Promise.all([p1, p2]).then(function (images) {
+    var lenna = images[0];
+    var bucket = images[1].scale(0.5);
+    
+    lenna.clone().blit(bucket, 0, 0).write("./output/blit1.png");
+    lenna.clone().blit(bucket, 50, 50, 50, 50, 128, 128).write("./output/blit2.png");
+    lenna.clone().blit(bucket, 0, 0, 50, 50, 128, 128).write("./output/blit3.png");
+}).catch(function (err) {
+    console.log(err);
+});

test/tests.sh

@@ -11,46 +11,48 @@ function clean {
 }
 
 clean
-echo "promise.js (1/10)"
+echo "promise.js (1/11)"
 node promise.js
 
 clean
-echo "callbacks.js (2/10)"
+echo "callbacks.js (2/11)"
 node callbacks.js
 
 clean
-echo "chained.js (3/10)"
+echo "chained.js (3/11)"
 node chained.js
 
 clean
-echo "create.js (4/10)"
+echo "create.js (4/11)"
 node create.js
 
 clean
-echo "rotation.js (5/10)"
+echo "rotation.js (5/11)"
 node rotation.js
 
 clean
-echo "filetype.js (6/10)"
+echo "filetype.js (6/11)"
 node filetypes.js
 
 clean
-echo "color.js (7/10)"
+echo "color.js (7/11)"
 node color.js
 
 clean
-echo "compare.js (8/10)"
+echo "compare.js (8/11)"
 node compare.js
 
 clean
-echo "exif.js (9/10)"
+echo "exif.js (9/11)"
 node exif.js
 
 clean
-echo "autocrop.js (10/10)"
+echo "autocrop.js (10/11)"
 node autocrop.js
 
-
+clean
+echo "blit.js (11/11)"
+node autocrop.js
 
 clean
 echo "done :-)"