Added saturate script function (+documentation), it also desaturates

doc/function/index.txt

@@ -67,7 +67,8 @@ These functions are built into the program, other [[type:function]]s can be defi
 | [[fun:combine_blend]]		Blend two images together using a given [[type:combine|combining mode]].
 | [[fun:set_mask]]		Set the transparancy mask of an image.
 | [[fun:set_alpha]]		Change the transparency of an image.
-| [[fun:set_combine]]		Chnage how the image should be combined with the background.
+| [[fun:set_combine]]		Change how the image should be combined with the background.
+| [[fun:saturate]]		Saturate/desaturate an image.
 | [[fun:enlarge]]		Enlarge an image by putting a border around it.
 | [[fun:crop]]		Crop an image, giving only a small subset of it.
 | [[fun:drop_shadow]]		Add a drop shadow to an image.

doc/function/saturate.txt

+Function: saturate
+
+--Usage--
+> saturate(input: image, amount: saturation amount)
+
+Saturate or desaturate an image. Saturation makes the colors brighter, desaturation makes the image more grey.
+
+To saturate use an amount between @0@ (no saturation) and @1@ (super crazy, too much saturation).
+
+To desaturate use an amount between @0@ (no desaturation) and @-1@ (convert to greyscale).
+
+--Parameters--
+! Parameter	Type			Description
+| @input@	[[type:image]]		Image to (de)saturate.
+| @alpha@	[[type:double]]		Saturation factor.
+
+--Examples--
+> saturate("image5.png", amount:  0.5)  ==  [[Image]]
+>>> saturate(<img src="image5.png" alt='"image5.png"' style="border:1px solid black;vertical-align:middle;margin:1px;" />, amount:  0.5) == <img src="image_saturate1.png" alt='"image_saturate1.png"' style="border:1px solid black;vertical-align:middle;margin:1px;" />
+> saturate("image5.png", amount: -0.5)  ==  [[Image]]
+>>> saturate(<img src="image5.png" alt='"image5.png"' style="border:1px solid black;vertical-align:middle;margin:1px;" />, amount: -0.5) == <img src="image_saturate2.png" alt='"image_saturate2.png"' style="border:1px solid black;vertical-align:middle;margin:1px;" />

src/gfx/generated_image.cpp

@@ -74,7 +74,7 @@ Image conform_image(const Image& img, const GeneratedImage::Options& options) {
 	}
 	// saturate?
 	if (options.saturate) {
-		saturate(image, 40);
+		saturate(image, .1);
 	}
 	options.width  = image.GetWidth();
 	options.height = image.GetHeight();
@@ -159,9 +159,6 @@ Image SetMaskImage::generate(const Options& opt) const {
 	set_alpha(img, mask->generate(opt));
 	return img;
 }
-ImageCombine SetMaskImage::combine() const {
-	return image->combine();
-}
 bool SetMaskImage::operator == (const GeneratedImage& that) const {
 	const SetMaskImage* that2 = dynamic_cast<const SetMaskImage*>(&that);
 	return that2 && *image == *that2->image
@@ -173,9 +170,6 @@ Image SetAlphaImage::generate(const Options& opt) const {
 	set_alpha(img, alpha);
 	return img;
 }
-ImageCombine SetAlphaImage::combine() const {
-	return image->combine();
-}
 bool SetAlphaImage::operator == (const GeneratedImage& that) const {
 	const SetAlphaImage* that2 = dynamic_cast<const SetAlphaImage*>(&that);
 	return that2 && *image == *that2->image
@@ -196,6 +190,19 @@ bool SetCombineImage::operator == (const GeneratedImage& that) const {
 	             && image_combine == that2->image_combine;
 }
 
+// ----------------------------------------------------------------------------- : SaturateImage
+
+Image SaturateImage::generate(const Options& opt) const {
+	Image img = image->generate(opt);
+	saturate(img, amount);
+	return img;
+}
+bool SaturateImage::operator == (const GeneratedImage& that) const {
+	const SaturateImage* that2 = dynamic_cast<const SaturateImage*>(&that);
+	return that2 && *image == *that2->image
+	             && amount == that2->amount;
+}
+
 // ----------------------------------------------------------------------------- : EnlargeImage
 
 Image EnlargeImage::generate(const Options& opt) const {

src/gfx/generated_image.hpp

@@ -66,6 +66,20 @@ class GeneratedImage : public ScriptValue {
 /// Resize an image to conform to the options
 Image conform_image(const Image&, const GeneratedImage::Options&);
 
+// ----------------------------------------------------------------------------- : SimpleFilterImage
+
+/// Apply some filter to a single image
+class SimpleFilterImage : public GeneratedImage {
+  public:
+	inline SimpleFilterImage(const GeneratedImageP& image)
+		: image(image)
+	{}
+	virtual ImageCombine combine() const { return image->combine(); }
+	virtual bool local() const { return image->local(); }
+  protected:
+	GeneratedImageP image;
+};
+
 // ----------------------------------------------------------------------------- : BlankImage
 
 /// An image generator that returns a blank image
@@ -133,51 +147,59 @@ class CombineBlendImage : public GeneratedImage {
 // ----------------------------------------------------------------------------- : SetMaskImage
 
 /// Change the alpha channel of an image
-class SetMaskImage : public GeneratedImage {
+class SetMaskImage : public SimpleFilterImage {
   public:
 	inline SetMaskImage(const GeneratedImageP& image, const GeneratedImageP& mask)
-		: image(image), mask(mask)
+		: SimpleFilterImage(image), mask(mask)
 	{}
 	virtual Image generate(const Options& opt) const;
-	virtual ImageCombine combine() const;
 	virtual bool operator == (const GeneratedImage& that) const;
-	virtual bool local() const { return image->local() && mask->local(); }
   private:
-	GeneratedImageP image, mask;
+	GeneratedImageP mask;
 };
 
 /// Change the alpha channel of an image
-class SetAlphaImage : public GeneratedImage {
+class SetAlphaImage : public SimpleFilterImage {
   public:
 	inline SetAlphaImage(const GeneratedImageP& image, double alpha)
-		: image(image), alpha(alpha)
+		: SimpleFilterImage(image), alpha(alpha)
 	{}
 	virtual Image generate(const Options& opt) const;
-	virtual ImageCombine combine() const;
 	virtual bool operator == (const GeneratedImage& that) const;
-	virtual bool local() const { return image->local(); }
   private:
-	GeneratedImageP image;
 	double alpha;
 };
 
 // ----------------------------------------------------------------------------- : SetCombineImage
 
 /// Change the combine mode
-class SetCombineImage : public GeneratedImage {
+class SetCombineImage : public SimpleFilterImage {
   public:
 	inline SetCombineImage(const GeneratedImageP& image, ImageCombine image_combine)
-		: image(image), image_combine(image_combine)
+		: SimpleFilterImage(image), image_combine(image_combine)
 	{}
 	virtual Image generate(const Options& opt) const;
 	virtual ImageCombine combine() const;
 	virtual bool operator == (const GeneratedImage& that) const;
-	virtual bool local() const { return image->local(); }
   private:
-	GeneratedImageP image;
 	ImageCombine image_combine;
 };
 
+// ----------------------------------------------------------------------------- : SaturateImage
+
+/// Saturate/desaturate an image
+class SaturateImage : public SimpleFilterImage {
+  public:
+	inline SaturateImage(const GeneratedImageP& image, double alpha)
+		: SimpleFilterImage(image), amount(amount)
+	{}
+	virtual Image generate(const Options& opt) const;
+	virtual bool operator == (const GeneratedImage& that) const;
+  private:
+	GeneratedImageP image;
+	double amount;
+};
+
 // ----------------------------------------------------------------------------- : EnlargeImage
 
 /// Enlarge an image by adding a border around it

src/gfx/gfx.hpp

@@ -92,11 +92,8 @@ void mask_blend(Image& img1, const Image& img2, const Image& mask);
 
 // ----------------------------------------------------------------------------- : Effects
 
-/// Saturate an image, amount should be in range [0...100]
-void saturate(Image& image, int amount);
-
-/// Desaturate an image
-void desaturate(Image& image);
+/// Saturate an image
+void saturate(Image& image, double amount);
 
 // ----------------------------------------------------------------------------- : Combining
 

src/gfx/image_effects.cpp

@@ -12,33 +12,38 @@
 
 // ----------------------------------------------------------------------------- : Saturation
 
-void saturate(Image& image, int amount) {
+void saturate(Image& image, double amount) {
 	if (amount == 0) return; // nothing to do
-	int factor = 300 / amount;
-	int div    = factor - 2;
-	// for each pixel...
 	Byte* pix = image.GetData();
 	Byte* end = pix + image.GetWidth() * image.GetHeight() * 3;
-	while (pix != end) {
-		int r = pix[0], g = pix[1], b = pix[2];
-		int r2 = (factor * r - g - b) / div;
-		int g2 = (factor * g - r - b) / div;
-		int b2 = (factor * b - r - g) / div;
-		pix[0] = col(r2);
-		pix[1] = col(g2);
-		pix[2] = col(b2);
-		pix += 3;
-	}
-}
-
-void desaturate(Image& image/*, int amount*/) {
-	Byte* pix = image.GetData();
-	Byte* end = pix + image.GetWidth() * image.GetHeight() * 3;
-	while (pix != end) {
-		int r = pix[0], g = pix[1], b = pix[2];
-		pix[0] = (r+r+g+b) / 4;
-		pix[1] = (g+r+g+b) / 4;
-		pix[2] = (b+r+g+b) / 4;
-		pix += 3;
+	if (amount > 0) {
+		amount = min(amount,0.99);
+		int factor = 256 * amount;
+		int div    = 768 - 3 * factor;
+		while (pix != end) {
+			int r = pix[0], g = pix[1], b = pix[2];
+			int avg = factor*(r+g+b);
+			pix[0] = col((768*r - avg) / div);
+			pix[1] = col((768*g - avg) / div);
+			pix[2] = col((768*b - avg) / div);
+			pix += 3;
+		}
+	} else if (amount < -0.99) {
+		while (pix != end) {
+			int r = pix[0], g = pix[1], b = pix[2];
+			pix[0] = pix[1] = pix[2] = (r+g+b)/3;
+			pix += 3;
+		}
+	} else {
+		int factor1 = 256 * -amount;
+		int factor2 = 768 - 3*factor1;
+		while (pix != end) {
+			int r = pix[0], g = pix[1], b = pix[2];
+			int avg = factor1*(r+g+b);
+			pix[0] = (factor2*r + avg) / 768;
+			pix[1] = (factor2*g + avg) / 768;
+			pix[2] = (factor2*b + avg) / 768;
+			pix += 3;
+		}
 	}
 }

src/gui/packages_window.cpp

@@ -277,7 +277,7 @@ class PackageIconRequest : public ThumbnailRequest {
 		Image resampled(16,16,false);
 		resample_preserve_aspect(image,resampled);
 		ti->icon = Bitmap(resampled);
-		desaturate(resampled);
+		saturate(resampled, -.75);
 		set_alpha(resampled,0.5);
 		ti->icon_grey = Bitmap(resampled);
 		list->Refresh(false);
@@ -318,7 +318,7 @@ void PackageUpdateList::initItems() {
 			image = load_resource_image(_("installer_group"));
 		}
 		ti.icon = Bitmap(image);
-		desaturate(image);
+		saturate(image, -.75);
 		set_alpha(image, 0.5);
 		ti.icon_grey = Bitmap(image);
 		if (p && !p->description->icon.Ok() && !p->description->icon_url.empty()) {

src/script/functions/image.cpp

@@ -79,6 +79,12 @@ SCRIPT_FUNCTION(set_combine) {
 	return new_intrusive2<SetCombineImage>(input, image_combine);
 }
 
+SCRIPT_FUNCTION(saturate) {
+	SCRIPT_PARAM_C(GeneratedImageP, input);
+	SCRIPT_PARAM(double, amount);
+	return new_intrusive2<SaturateImage>(input, amount);
+}
+
 SCRIPT_FUNCTION(enlarge) {
 	SCRIPT_PARAM_C(GeneratedImageP, input);
 	SCRIPT_PARAM_N(double, _("border size"), border_size);
@@ -170,6 +176,7 @@ void init_script_image_functions(Context& ctx) {
 	ctx.setVariable(_("set mask"),         script_set_mask);
 	ctx.setVariable(_("set alpha"),        script_set_alpha);
 	ctx.setVariable(_("set combine"),      script_set_combine);
+	ctx.setVariable(_("saturate"),         script_saturate);
 	ctx.setVariable(_("enlarge"),          script_enlarge);
 	ctx.setVariable(_("crop"),             script_crop);
 	ctx.setVariable(_("drop shadow"),      script_drop_shadow);