Add leaveBorder to AutoCrop (#399)

* autocropnew added with possibility to define a border area left uncropped

* Test added/copied the original, not that effective. "autocropnew" features tested in real life though

* added autocropnew to readme

* Add symmetric auto cropping.

* Add configuration of autocrop via options object
* Add symmetric autocrop

* Adapt type definition to changes

* Fix lint errors

* update docs

* add test

packages/jimp/README.md

@@ -128,7 +128,7 @@ image.scaleToFit( w, h[, mode] ); // scale the image to the largest size that fi
 
 /* Crop */
 image.autocrop([tolerance, frames]); // automatically crop same-color borders from image (if any), frames must be a Boolean
-image.autocrop(options);          // automatically crop same-color borders from image (if any), options may contain tolerance, cropOnlyFrames, cropSymmetric
+image.autocrop(options);          // automatically crop same-color borders from image (if any), options may contain tolerance, cropOnlyFrames, cropSymmetric, leaveBorder
 image.crop( x, y, w, h );         // crop to the given region
 
 /* Composing */

packages/jimp/jimp.d.ts

@@ -432,7 +432,8 @@ declare namespace Jimp {
       options: {
         tolerance?: number;
         cropOnlyFrames?: boolean;
-        cropSymmetric: boolean;
+        cropSymmetric?: boolean;
+        leaveBorder?: number;
       },
       cb?: Jimp.ImageCallback
     ): this;

packages/plugin-crop/src/index.js

@@ -68,6 +68,7 @@ export default function pluginCrop(event) {
         const minPixelsPerSide = 1; // to avoid cropping completely the image, resulting in an invalid 0 sized image
 
         let cb; // callback
+        let leaveBorder = 0; // Amount of pixels in border to leave
         let tolerance = 0.0002; // percent of color difference tolerance (default value)
         let cropOnlyFrames = true; // flag to force cropping only if the image has a real "frame"
         // i.e. all 4 sides have some border (default value)
@@ -106,6 +107,10 @@ export default function pluginCrop(event) {
             if (typeof config.cropSymmetric !== 'undefined') {
               ({ cropSymmetric } = config);
             }
+
+            if (typeof config.leaveBorder !== 'undefined') {
+              ({ leaveBorder } = config);
+            }
           }
         }
 
@@ -135,6 +140,7 @@ export default function pluginCrop(event) {
 
             if (this.constructor.colorDiff(rgba1, rgba2) > tolerance) {
               // this pixel is too distant from the first one: abort this side scan
+              northPixelsToCrop -= leaveBorder;
               break north;
             }
           }
@@ -151,6 +157,7 @@ export default function pluginCrop(event) {
 
             if (this.constructor.colorDiff(rgba1, rgba2) > tolerance) {
               // this pixel is too distant from the first one: abort this side scan
+              eastPixelsToCrop -= leaveBorder;
               break east;
             }
           }
@@ -171,6 +178,7 @@ export default function pluginCrop(event) {
 
             if (this.constructor.colorDiff(rgba1, rgba2) > tolerance) {
               // this pixel is too distant from the first one: abort this side scan
+              southPixelsToCrop -= leaveBorder;
               break south;
             }
           }
@@ -191,6 +199,7 @@ export default function pluginCrop(event) {
 
             if (this.constructor.colorDiff(rgba1, rgba2) > tolerance) {
               // this pixel is too distant from the first one: abort this side scan
+              westPixelsToCrop -= leaveBorder;
               break west;
             }
           }

packages/plugin-crop/test/autocrop.test.js

@@ -222,7 +222,7 @@ describe('Autocrop', () => {
       );
   });
 
-  it('image wihtout frame and with symmetric border configured by options', async () => {
+  it('image without frame and with symmetric border configured by options', async () => {
     const imgSrc = await Jimp.read(
       mkJGD(
         '▥▥   ◆◆   ▥▥▥▥',
@@ -249,4 +249,38 @@ describe('Autocrop', () => {
         )
       );
   });
+
+  it('image without frame and with with some border left', async () => {
+    const imgSrc = await Jimp.read(
+      mkJGD(
+        '323232323232',
+        '232323232323',
+        '32   ◆◆   32',
+        '23  ◆▦▦◆  23',
+        '32 ◆▦▦▦▦◆ 32',
+        '23  ◆▦▦◆  23',
+        '32   ◆◆   32',
+        '232323232323',
+        '323232323232'
+      )
+    );
+
+    imgSrc
+      .autocrop({
+        tolerance: 0.005,
+        leaveBorder: 1
+      })
+      .getJGDSync()
+      .should.be.sameJGD(
+        mkJGD(
+          '3232323232',
+          '2   ◆◆   3',
+          '3  ◆▦▦◆  2',
+          '2 ◆▦▦▦▦◆ 3',
+          '3  ◆▦▦◆  2',
+          '2   ◆◆   3',
+          '3232323232'
+        )
+      );
+  });
 });