Enable hsl shifting of named images

atom/common/api/atom_api_native_image_mac.mm

@@ -7,23 +7,50 @@
 #import <Cocoa/Cocoa.h>
 
 #include "base/strings/sys_string_conversions.h"
+#include "ui/gfx/color_utils.h"
+#include "ui/gfx/image/image.h"
+#include "ui/gfx/image/image_skia.h"
+#include "ui/gfx/image/image_skia_operations.h"
 
 namespace atom {
 
 namespace api {
 
+NSData* bufferFromNSImage(NSImage* image) {
+  CGImageRef ref = [image CGImageForProposedRect:nil context:nil hints:nil];
+  NSBitmapImageRep* rep = [[NSBitmapImageRep alloc] initWithCGImage:ref];
+  [rep setSize:[image size]];
+  return [rep representationUsingType:NSPNGFileType properties:[[NSDictionary alloc] init]];
+}
+
+double safeShift(double in, double def) {
+  if (in >= 0 || in <= 1 || in == def) return in;
+  return def;
+}
+
 mate::Handle<NativeImage> NativeImage::CreateFromNamedImage(
   mate::Arguments* args, const std::string& name) {
   @autoreleasepool {
+    std::vector<double> hsl_shift;
     NSImage* image = [NSImage imageNamed:base::SysUTF8ToNSString(name)];
     if (!image.valid) {
       return CreateEmpty(args->isolate());
     }
 
-    CGImageRef ref = [image CGImageForProposedRect:nil context:nil hints:nil];
-    NSBitmapImageRep* rep = [[NSBitmapImageRep alloc] initWithCGImage:ref];
-    [rep setSize:[image size]];
-    NSData* pngData = [rep representationUsingType:NSPNGFileType properties:[[NSDictionary alloc] init]];
+    NSData* pngData = bufferFromNSImage(image);
+
+    if (args->GetNext(&hsl_shift) && hsl_shift.size() == 3) {
+      gfx::Image gfxImage = gfx::Image::CreateFrom1xPNGBytes(
+        reinterpret_cast<const unsigned char*>((char *) [pngData bytes]), [pngData length]);
+      color_utils::HSL shift = {
+        safeShift(hsl_shift[0], -1),
+        safeShift(hsl_shift[1], 0.5),
+        safeShift(hsl_shift[2], 0.5)
+      };
+      pngData = bufferFromNSImage(gfx::Image(
+        gfx::ImageSkiaOperations::CreateHSLShiftedImage(
+          gfxImage.AsImageSkia(), shift)).CopyNSImage());
+    }
 
     return CreateFromPNG(args->isolate(), (char *) [pngData bytes], [pngData length]);
   }

docs/api/native-image.md

@@ -157,9 +157,10 @@ Returns `NativeImage`
 
 Creates a new `NativeImage` instance from `dataURL`.
 
-### `nativeImage.createFromNamedImage(imageName)` _macOS_
+### `nativeImage.createFromNamedImage(imageName[, hslShift])` _macOS_
 
 * `imageName` String
+* `hslShift` Number[]
 
 Returns `NativeImage`
 
@@ -167,6 +168,23 @@ Creates a new `NativeImage` instance from the NSImage that maps to the
 given image name.  See [`NSImageName`](https://developer.apple.com/documentation/appkit/nsimagename?language=objc)
 for a list of possible values.
 
+The `hslShift` is applied to the image with the following rules
+* `hsl_shift[0]` (hue): The absolute hue value for the image - 0 and 1 map
+     to 0 and 360 on the hue color wheel (red).
+* `hsl_shift[1]` (saturation): A saturation shift for the image, with the
+    following key values:  
+    0 = remove all color.  
+    0.5 = leave unchanged.  
+    1 = fully saturate the image.  
+* `hsl_shift[2]` (lightness): A lightness shift for the image, with the
+    following key values:  
+    0 = remove all lightness (make all pixels black).  
+    0.5 = leave unchanged.  
+    1 = full lightness (make all pixels white).
+
+This means that `[-1, 0, 1]` will make the image completely white and
+`[-1, 1, 0]` will make the image completely black.
+
 ## Class: NativeImage
 
 > Natively wrap images such as tray, dock, and application icons.