From b7a6ddc8fadb22132d963d00732aca18e1a16edf Mon Sep 17 00:00:00 2001
From: Matthias Grosser <mtgrosser@gmx.net>
Date: Tue, 15 Mar 2022 21:53:03 +0100
Subject: [PATCH 1/4] Image blending

---
 CHANGELOG.md        |   5 +-
 ext/rszr/image.c    | 158 ++++++++++++++++++++++++++++++++++++++++----
 lib/rszr/color.rb   |  56 ++++++++++++++--
 lib/rszr/image.rb   |  19 +++++-
 lib/rszr/version.rb |   2 +-
 5 files changed, 219 insertions(+), 21 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4e338aa..7bcf6ff 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,9 @@
-## Rszr 1.2.1 (unreleased)
+## Rszr 1.3.0 (unreleased)
 
 * Fix saving without extension (@mantas)
+* Alpha channel control
+* Background initialization
+* Image blending
 
 ## Rszr 1.2.0 (Mar 11, 2022)
 
diff --git a/ext/rszr/image.c b/ext/rszr/image.c
index 622906e..1677ab8 100644
--- a/ext/rszr/image.c
+++ b/ext/rszr/image.c
@@ -34,7 +34,7 @@ static VALUE rszr_image_s_allocate(VALUE klass)
 }
 
 
-static VALUE rszr_image_initialize(VALUE self, VALUE rb_width, VALUE rb_height)
+static VALUE rszr_image__initialize(VALUE self, VALUE rb_width, VALUE rb_height)
 {
   rszr_image_handle * handle;
   
@@ -98,7 +98,6 @@ static VALUE rszr_image__format_get(VALUE self)
   }
 }
 
-
 static VALUE rszr_image__format_set(VALUE self, VALUE rb_format)
 {
   rszr_image_handle * handle;
@@ -113,6 +112,54 @@ static VALUE rszr_image__format_set(VALUE self, VALUE rb_format)
 }
 
 
+static void rszr_image_color_set(VALUE rb_Color)
+{
+  VALUE rb_cColorBase;
+  int r, g, b, a;
+
+  rb_cColorBase = rb_path2class("Rszr::Color::Base");
+
+  if(!rb_obj_is_kind_of(rb_Color, rb_cColorBase) || RBASIC_CLASS(rb_Color) == rb_cColorBase) {
+    rb_raise(rb_eArgError, "color must descend from Rszr::Color::Base");
+  }
+
+  r = FIX2INT(rb_funcall(rb_Color, rb_intern("red"), 0));
+  g = FIX2INT(rb_funcall(rb_Color, rb_intern("green"), 0));
+  b = FIX2INT(rb_funcall(rb_Color, rb_intern("blue"), 0));
+  a = FIX2INT(rb_funcall(rb_Color, rb_intern("alpha"), 0));
+
+  // TODO: use color model specific setter function
+  imlib_context_set_color(r, g, b, a);
+}
+
+
+static VALUE rszr_image_alpha_get(VALUE self)
+{
+  rszr_image_handle * handle;
+
+  Data_Get_Struct(self, rszr_image_handle, handle);
+
+  imlib_context_set_image(handle->image);
+  if (imlib_image_has_alpha()) {
+    return Qtrue;
+  }
+
+  return Qfalse;
+}
+
+static VALUE rszr_image_alpha_set(VALUE self, VALUE rb_alpha)
+{
+  rszr_image_handle * handle;
+
+  Data_Get_Struct(self, rszr_image_handle, handle);
+
+  imlib_context_set_image(handle->image);
+  imlib_image_set_has_alpha(RTEST(rb_alpha) ? 1 : 0);
+
+  return Qnil;
+}
+
+
 static VALUE rszr_image_width(VALUE self)
 {
   rszr_image_handle * handle;
@@ -357,6 +404,7 @@ static Imlib_Image rszr_create_cropped_scaled_image(const Imlib_Image image, VAL
 
   imlib_context_set_image(image);
   imlib_context_set_anti_alias(1);
+  imlib_context_set_dither(1);
   resized_image = imlib_create_cropped_scaled_image(src_x, src_y, src_w, src_h, dst_w, dst_h);
   
   if (!resized_image) {
@@ -400,6 +448,11 @@ static Imlib_Image rszr_create_cropped_image(const Imlib_Image image, VALUE rb_x
 {
   Imlib_Image cropped_image;
   
+  Check_Type(rb_x, T_FIXNUM);
+  Check_Type(rb_y, T_FIXNUM);
+  Check_Type(rb_w, T_FIXNUM);
+  Check_Type(rb_h, T_FIXNUM);
+
   int x = NUM2INT(rb_x);
   int y = NUM2INT(rb_y);
   int w = NUM2INT(rb_w);
@@ -445,6 +498,85 @@ static VALUE rszr_image__crop(VALUE self, VALUE bang, VALUE rb_x, VALUE rb_y, VA
 }
 
 
+static VALUE rszr_image__blend(VALUE self, VALUE other, VALUE rb_merge_alpha, VALUE rb_mode,
+                               VALUE rb_src_x, VALUE rb_src_y, VALUE rb_src_w, VALUE rb_src_h,
+                               VALUE rb_dst_x, VALUE rb_dst_y, VALUE rb_dst_w, VALUE rb_dst_h)
+{
+  rszr_image_handle * handle;
+  rszr_image_handle * other_handle;
+  Imlib_Operation operation;
+
+  Check_Type(rb_operation, T_FIXNUM);
+  Check_Type(rb_src_x, T_FIXNUM);
+  Check_Type(rb_src_y, T_FIXNUM);
+  Check_Type(rb_src_w, T_FIXNUM);
+  Check_Type(rb_src_h, T_FIXNUM);
+  Check_Type(rb_dst_x, T_FIXNUM);
+  Check_Type(rb_dst_y, T_FIXNUM);
+  Check_Type(rb_dst_w, T_FIXNUM);
+  Check_Type(rb_dst_h, T_FIXNUM);
+
+  operation = (Imlib_Operation) NUM2INT(rb_mode);
+  int src_x = NUM2INT(rb_src_x);
+  int src_y = NUM2INT(rb_src_y);
+  int src_w = NUM2INT(rb_src_w);
+  int src_h = NUM2INT(rb_src_h);
+  int dst_x = NUM2INT(rb_dst_x);
+  int dst_y = NUM2INT(rb_dst_y);
+  int dst_w = NUM2INT(rb_dst_w);
+  int dst_h = NUM2INT(rb_dst_h);
+
+  char merge_alpha = RTEST(rb_merge_alpha) ? 1 : 0;
+
+  Data_Get_Struct(self, rszr_image_handle, handle);
+  Data_Get_Struct(other, rszr_image_handle, other_handle);
+
+  imlib_context_set_image(handle->image);
+  imlib_context_set_operation(operation);
+  imlib_blend_image_onto_image(other_handle->image, merge_alpha, src_x, src_y, src_w, src_h, dst_x, dst_y, dst_w, dst_h);
+
+  return self;
+}
+
+
+static VALUE rszr_image_rectangle_bang(VALUE self, VALUE rb_color, VALUE rb_x, VALUE rb_y, VALUE rb_w, VALUE rb_h)
+{
+  rszr_image_handle * handle;
+
+  Check_Type(rb_x, T_FIXNUM);
+  Check_Type(rb_y, T_FIXNUM);
+  Check_Type(rb_w, T_FIXNUM);
+  Check_Type(rb_h, T_FIXNUM);
+
+  int x = NUM2INT(rb_x);
+  int y = NUM2INT(rb_y);
+  int w = NUM2INT(rb_w);
+  int h = NUM2INT(rb_h);
+
+  Data_Get_Struct(self, rszr_image_handle, handle);
+
+  imlib_context_set_image(handle->image);
+  rszr_image_color_set(rb_color);
+  imlib_image_fill_rectangle(x, y, w, h);
+
+  return self;
+}
+
+
+static VALUE rszr_image_fill_bang(VALUE self, VALUE rb_color)
+{
+  rszr_image_handle * handle;
+
+  Data_Get_Struct(self, rszr_image_handle, handle);
+
+  imlib_context_set_image(handle->image);
+  rszr_image_color_set(rb_color);
+  imlib_image_fill_rectangle(0, 0, imlib_image_get_width(), imlib_image_get_height());
+
+  return self;
+}
+
+
 static VALUE rszr_image__save(VALUE self, VALUE rb_path, VALUE rb_format, VALUE rb_quality, VALUE rb_interlace)
 {
   rszr_image_handle * handle;
@@ -487,27 +619,29 @@ void Init_rszr_image()
   rb_define_private_method(rb_singleton_class(cImage), "_load", rszr_image_s__load, 1);
 
   // Instance methods
-  rb_define_method(cImage, "initialize",  rszr_image_initialize, 2);
   rb_define_method(cImage, "width",       rszr_image_width, 0);
   rb_define_method(cImage, "height",      rszr_image_height, 0);
   rb_define_method(cImage, "dup",         rszr_image_dup, 0);
   rb_define_method(cImage, "filter!",     rszr_image_filter_bang, 1);
   rb_define_method(cImage, "flop!",       rszr_image_flop_bang, 0);
   rb_define_method(cImage, "flip!",       rszr_image_flip_bang, 0);
+  rb_define_method(cImage, "rectangle!",  rszr_image_rectangle_bang, 5);
+  rb_define_method(cImage, "fill!",       rszr_image_fill_bang, 1);
   
-  // rb_define_method(cImage, "quality",     rszr_image_get_quality, 0);
-  // rb_define_method(cImage, "quality=",    rszr_image_set_quality, 1);
+  rb_define_method(cImage, "alpha",   rszr_image_alpha_get, 0);
+  rb_define_method(cImage, "alpha=",  rszr_image_alpha_set, 1);
   
   rb_define_protected_method(cImage, "_format",  rszr_image__format_get, 0);
   rb_define_protected_method(cImage, "_format=", rszr_image__format_set, 1);
   
-  rb_define_private_method(cImage, "_resize",  rszr_image__resize, 7);
-  rb_define_private_method(cImage, "_crop",    rszr_image__crop, 5);
-  rb_define_private_method(cImage, "_turn!",   rszr_image__turn_bang, 1);
-  rb_define_private_method(cImage, "_rotate",    rszr_image__rotate, 2);
-  rb_define_private_method(cImage, "_sharpen!",  rszr_image__sharpen_bang, 1);
-  rb_define_private_method(cImage, "_pixel",     rszr_image__pixel_get, 2);
-  
+  rb_define_private_method(cImage, "_initialize", rszr_image__initialize, 2);
+  rb_define_private_method(cImage, "_resize",     rszr_image__resize, 7);
+  rb_define_private_method(cImage, "_crop",       rszr_image__crop, 5);
+  rb_define_private_method(cImage, "_turn!",      rszr_image__turn_bang, 1);
+  rb_define_private_method(cImage, "_rotate",     rszr_image__rotate, 2);
+  rb_define_private_method(cImage, "_sharpen!",   rszr_image__sharpen_bang, 1);
+  rb_define_private_method(cImage, "_pixel",      rszr_image__pixel_get, 2);
+  rb_define_private_method(cImage, "_blend",      rszr_image__blend, 11);
   rb_define_private_method(cImage, "_save",       rszr_image__save, 4);
 }
 
diff --git a/lib/rszr/color.rb b/lib/rszr/color.rb
index 9e911fa..3f8f866 100644
--- a/lib/rszr/color.rb
+++ b/lib/rszr/color.rb
@@ -1,8 +1,12 @@
 module Rszr
   module Color
 
-    class RGBA
-      attr_reader :red, :green, :blue, :alpha
+    class Base
+      attr_reader :alpha
+    end
+
+    class RGBA < Base
+      attr_reader :red, :green, :blue
 
       def initialize(red, green, blue, alpha = 255)
         if red < 0 || red > 255 || green < 0 || green > 255 || blue < 0 || blue > 255 || alpha < 0 || alpha > 255
@@ -10,16 +14,56 @@ def initialize(red, green, blue, alpha = 255)
         end
         @red, @green, @blue, @alpha = red, green, blue, alpha
       end
-      
-      def to_i(rgb: false)
+
+      def cyan
+        255 - red
+      end
+
+      def magenta
+        255 - green
+      end
+
+      def yellow
+        255 - blue
+      end
+
+      def to_i(alpha: true)
         i = red.to_i << 24 | green.to_i << 16 | blue.to_i << 8 | alpha.to_i
-        rgb ? i >> 8 : i
+        alpha ? i : i >> 8
       end
-      
+
       def to_hex(rgb: false)
         "%0#{rgb ? 6 : 8}x" % to_i(rgb: rgb)
       end
     end
 
+    class CMYA < Base
+      attr_reader :cyan, :magenta, :yellow
+
+      def initialize(cyan, magenta, yellow, alpha = 255)
+        if cyan < 0 || cyan > 255 || magenta < 0 || magenta > 255 || yellow < 0 || yellow > 255 || alpha < 0 || alpha > 255
+          raise ArgumentError, 'color out of range'
+        end
+        @cyan, @magenta, @yellow = cyan, magenta, yellow
+      end
+
+      def red
+        255 - cyan
+      end
+
+      def green
+        255 - magenta
+      end
+
+      def blue
+        255 - yellow
+      end
+
+    end
+
+    Transparent = RGBA.new(0, 0, 0, 0)
+    White = RGBA.new(255,255,255)
+    Black = RGBA.new(0, 0, 0)
+
   end
 end
diff --git a/lib/rszr/image.rb b/lib/rszr/image.rb
index 59ff2e6..3f1c535 100644
--- a/lib/rszr/image.rb
+++ b/lib/rszr/image.rb
@@ -1,6 +1,7 @@
 module Rszr
   class Image
     GRAVITIES = [true, :center, :n, :nw, :w, :sw, :s, :se, :e, :ne].freeze
+    BLENDING_MODES = %i[copy add subtract reshade].freeze
     
     extend Identification
     include Buffered
@@ -40,6 +41,8 @@ def format=(fmt)
       self._format = fmt
     end
     
+    alias_method :alpha?, :alpha
+    
     def [](x, y)
       if x >= 0 && x <= width - 1 && y >= 0 && y <= height - 1
         Color::RGBA.new(*_pixel(x, y))
@@ -49,7 +52,7 @@ def [](x, y)
     def inspect
       fmt = format
       fmt = " #{fmt.upcase}" if fmt
-      "#<#{self.class.name}:0x#{object_id.to_s(16)} #{width}x#{height}#{fmt}>"
+      "#<#{self.class.name}:0x#{object_id.to_s(16)} #{width}x#{height}x#{alpha? ? 32 : 24}#{fmt}>"
     end
 
     module Transformations
@@ -144,10 +147,24 @@ def gamma!(value, r: nil, g: nil, b: nil, a: nil)
       def gamma(*args, **opts)
         dup.gamma!(*args, **opts)
       end
+      
+      def blend(image, mode: :copy)
+        raise ArgumentError, "mode must be one of #{BLENDING_MODES.map(&:to_s).join(', ')}" unless BLENDING_MODES.include?(mode)
+        _blend(image, true, BLENDING_MODES.index(mode), 0, 0, image.width, image.height, 0, 0, image.width, image.height)
+      end
     end
     
     include Transformations
 
+    def initialize(width, height, alpha: false, background: nil)
+      raise ArgumentError, 'illegal image dimensions' if width < 1 || width > 32766 || height < 1 || height > 32766
+      raise ArgumentError, 'background must descend from Rszr::Color::Base' if background && !(background.class < Color::Base)
+      _initialize(width, height).tap do |image|
+        image.alpha = alpha
+        image.fill!(background) if background
+      end
+    end
+
     def save(path, format: nil, quality: nil, interlace: false)
       format ||= format_from_filename(path) || self.format || 'jpg'
       raise ArgumentError, "invalid quality #{quality.inspect}" if quality && !(0..100).cover?(quality)
diff --git a/lib/rszr/version.rb b/lib/rszr/version.rb
index 63d0925..3e1b1db 100644
--- a/lib/rszr/version.rb
+++ b/lib/rszr/version.rb
@@ -1,3 +1,3 @@
 module Rszr
-  VERSION = '1.2.1'
+  VERSION = '1.3.0'
 end

From 87f13b2be2db9db8473a734a79f91a7dc0eae06a Mon Sep 17 00:00:00 2001
From: Matthias Grosser <mtgrosser@gmx.net>
Date: Tue, 15 Mar 2022 22:22:38 +0100
Subject: [PATCH 2/4] Fix variable name

---
 ext/rszr/image.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/ext/rszr/image.c b/ext/rszr/image.c
index 1677ab8..1d60a6f 100644
--- a/ext/rszr/image.c
+++ b/ext/rszr/image.c
@@ -506,7 +506,7 @@ static VALUE rszr_image__blend(VALUE self, VALUE other, VALUE rb_merge_alpha, VA
   rszr_image_handle * other_handle;
   Imlib_Operation operation;
 
-  Check_Type(rb_operation, T_FIXNUM);
+  Check_Type(rb_mode,  T_FIXNUM);
   Check_Type(rb_src_x, T_FIXNUM);
   Check_Type(rb_src_y, T_FIXNUM);
   Check_Type(rb_src_w, T_FIXNUM);
@@ -593,6 +593,7 @@ static VALUE rszr_image__save(VALUE self, VALUE rb_path, VALUE rb_format, VALUE
   
   imlib_context_set_image(handle->image);
   imlib_image_set_format(format);
+
   if (quality)
     imlib_image_attach_data_value("quality", NULL, quality, NULL);
 

From df87e2af6790bc3bdcab7e3829c7b8dd7152c2b7 Mon Sep 17 00:00:00 2001
From: Matthias Grosser <mtgrosser@gmx.net>
Date: Fri, 25 Mar 2022 12:25:21 +0100
Subject: [PATCH 3/4] Gradients

---
 CHANGELOG.md               |   2 +
 README.md                  |  33 ++++++++++-
 ext/rszr/errors.c          |   4 +-
 ext/rszr/image.c           | 109 +++++++++++++++++++++++++++----------
 lib/rszr.rb                |   3 +-
 lib/rszr/color.rb          |  66 ++--------------------
 lib/rszr/color/base.rb     |  21 +++++++
 lib/rszr/color/cmya.rb     |  29 ++++++++++
 lib/rszr/color/gradient.rb |  40 ++++++++++++++
 lib/rszr/color/point.rb    |  29 ++++++++++
 lib/rszr/color/rgba.rb     |  44 +++++++++++++++
 lib/rszr/fill.rb           |  21 +++++++
 lib/rszr/image.rb          |  21 ++++++-
 13 files changed, 328 insertions(+), 94 deletions(-)
 create mode 100644 lib/rszr/color/base.rb
 create mode 100644 lib/rszr/color/cmya.rb
 create mode 100644 lib/rszr/color/gradient.rb
 create mode 100644 lib/rszr/color/point.rb
 create mode 100644 lib/rszr/color/rgba.rb
 create mode 100644 lib/rszr/fill.rb

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7bcf6ff..0547431 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,8 @@
 * Alpha channel control
 * Background initialization
 * Image blending
+* Rectangle and image fills
+* Color gradients
 
 ## Rszr 1.2.0 (Mar 11, 2022)
 
diff --git a/README.md b/README.md
index 8e50ac9..36ec4c5 100644
--- a/README.md
+++ b/README.md
@@ -121,6 +121,36 @@ image.flop
 image.dup
 ```
 
+### Image generation
+
+```ruby
+# generate new image with transparent background
+image = Rszr::Image.new(500, 500, alpha: true, background: Rszr::Color::Transparent)
+
+# fill image with 50% opacity
+image.fill!(Rszr::Color::RGBA.new(0, 206, 209, 50))
+
+# define a color gradient
+gradient = Rszr::Color::Gradient.new do |g|
+  g.point 0, 255, 250, 205, 50
+  g.point 0.5, 135, 206, 250
+  g.point 1, Rszr::Color::White
+end
+
+# draw a rectangle and fill it using the gradient with 45°
+image.rectangle!(gradient.to_fill(45), 100, 100, 300, 300)
+```
+
+### Watermarking
+
+```ruby
+# load logo
+logo = Rszr::Image.load('logo.png')
+
+# blend it onto the image at position (10, 10)
+image.blend(logo, 10, 10)
+```
+
 ### Filters
 
 Filters also support bang! and non-bang methods.
@@ -170,8 +200,7 @@ In order to save interlaced PNGs and progressive JPEGs, set the `interlace` opti
 image.save('interlaced.png', interlace: true)
 ```
 
-As of v1.8.0, `imlib2` doesn't support saving progressive JPEG images yet,
-but a [patch](https://git.enlightenment.org/legacy/imlib2.git/commit/?id=37e8c9578897259211284d3590cc38b7f6a718dc) has been submitted.
+Saving progressive JPEG images requires `imlib2` >= 1.8.1.
 
 For EL8, there are pre-built RPMs provided by the [onrooby repo](http://downloads.onrooby.com/repo/el/8/x86_64/).
 
diff --git a/ext/rszr/errors.c b/ext/rszr/errors.c
index 6ebec83..f2cbb27 100644
--- a/ext/rszr/errors.c
+++ b/ext/rszr/errors.c
@@ -5,6 +5,7 @@
 #include "errors.h"
 
 VALUE eRszrError = Qnil;
+VALUE eRszrInternalError = Qnil;
 VALUE eRszrFileNotFound = Qnil;
 VALUE eRszrTransformationError = Qnil;
 VALUE eRszrErrorWithMessage = Qnil;
@@ -33,11 +34,12 @@ const int RSZR_MAX_ERROR_INDEX = 13;
 void Init_rszr_errors()
 {
   eRszrError = rb_define_class_under(mRszr, "Error", rb_eStandardError);
+  eRszrInternalError = rb_define_class_under(mRszr, "InternalError", eRszrError);
   eRszrFileNotFound = rb_define_class_under(mRszr, "FileNotFound", eRszrError);
   eRszrTransformationError = rb_define_class_under(mRszr, "TransformationError", eRszrError);
   eRszrErrorWithMessage = rb_define_class_under(mRszr, "ErrorWithMessage", eRszrError);
   eRszrLoadError = rb_define_class_under(mRszr, "LoadError", eRszrErrorWithMessage);
-  eRszrSaveError = rb_define_class_under(mRszr, "SaveError", eRszrErrorWithMessage);
+  eRszrSaveError = rb_define_class_under(mRszr, "SaveError", eRszrErrorWithMessage);  
 }
 
 static void rszr_raise_error_with_message(VALUE rb_error_class, Imlib_Load_Error error)
diff --git a/ext/rszr/image.c b/ext/rszr/image.c
index 1d60a6f..3655802 100644
--- a/ext/rszr/image.c
+++ b/ext/rszr/image.c
@@ -6,6 +6,10 @@
 #include "errors.h"
 
 VALUE cImage = Qnil;
+VALUE cColorBase = Qnil;
+VALUE cColorGradient = Qnil;
+VALUE cColorPoint = Qnil;
+VALUE cFill = Qnil;
 
 
 static void rszr_free_image(Imlib_Image image)
@@ -112,21 +116,18 @@ static VALUE rszr_image__format_set(VALUE self, VALUE rb_format)
 }
 
 
-static void rszr_image_color_set(VALUE rb_Color)
+static void rszr_image_color_set(VALUE rb_color)
 {
-  VALUE rb_cColorBase;
   int r, g, b, a;
 
-  rb_cColorBase = rb_path2class("Rszr::Color::Base");
-
-  if(!rb_obj_is_kind_of(rb_Color, rb_cColorBase) || RBASIC_CLASS(rb_Color) == rb_cColorBase) {
+  if(!rb_obj_is_kind_of(rb_color, cColorBase) || RBASIC_CLASS(rb_color) == cColorBase) {
     rb_raise(rb_eArgError, "color must descend from Rszr::Color::Base");
   }
 
-  r = FIX2INT(rb_funcall(rb_Color, rb_intern("red"), 0));
-  g = FIX2INT(rb_funcall(rb_Color, rb_intern("green"), 0));
-  b = FIX2INT(rb_funcall(rb_Color, rb_intern("blue"), 0));
-  a = FIX2INT(rb_funcall(rb_Color, rb_intern("alpha"), 0));
+  r = FIX2INT(rb_funcall(rb_color, rb_intern("red"), 0));
+  g = FIX2INT(rb_funcall(rb_color, rb_intern("green"), 0));
+  b = FIX2INT(rb_funcall(rb_color, rb_intern("blue"), 0));
+  a = FIX2INT(rb_funcall(rb_color, rb_intern("alpha"), 0));
 
   // TODO: use color model specific setter function
   imlib_context_set_color(r, g, b, a);
@@ -539,9 +540,57 @@ static VALUE rszr_image__blend(VALUE self, VALUE other, VALUE rb_merge_alpha, VA
 }
 
 
-static VALUE rszr_image_rectangle_bang(VALUE self, VALUE rb_color, VALUE rb_x, VALUE rb_y, VALUE rb_w, VALUE rb_h)
+static Imlib_Color_Range rszr_image_init_color_range(VALUE rb_gradient)
+{
+  Imlib_Color_Range range;
+  VALUE rb_points;
+  VALUE rb_point;
+  VALUE rb_color;
+  int size, i;
+  double position;
+  int red, green, blue, alpha;
+
+  if(!rb_obj_is_kind_of(rb_gradient, cColorGradient)) {
+    rb_raise(rb_eArgError, "color must be a Rszr::Color::Gradient");
+  }
+
+  rb_points = rb_funcall(rb_gradient, rb_intern("points"), 0);
+  Check_Type(rb_points, T_ARRAY);
+
+  imlib_context_get_color(&red, &green, &blue, &alpha);
+
+  range = imlib_create_color_range();
+  imlib_context_set_color_range(range);
+
+  size = RARRAY_LEN(rb_points);
+  for (i = 0; i < size; i++) {
+    rb_point = rb_ary_entry(rb_points, i);
+    if(!rb_obj_is_kind_of(rb_point, cColorPoint))
+      rb_raise(rb_eArgError, "point must be a Rszr::Color::Point");
+
+    rb_color = rb_funcall(rb_point, rb_intern("color"), 0);
+    if(!rb_obj_is_kind_of(rb_color, cColorBase) || RBASIC_CLASS(rb_color) == cColorBase)
+      rb_raise(rb_eArgError, "color must descend from Rszr::Color::Base");
+
+    position = NUM2DBL(rb_funcall(rb_point, rb_intern("position"), 0));
+
+    rszr_image_color_set(rb_color);
+    imlib_add_color_to_color_range(position * 255);
+  }
+
+  imlib_context_set_color(red, green, blue, alpha);
+
+  return range;
+}
+
+
+static VALUE rszr_image__rectangle_bang(VALUE self, VALUE rb_fill, VALUE rb_x, VALUE rb_y, VALUE rb_w, VALUE rb_h)
 {
   rszr_image_handle * handle;
+  VALUE rb_gradient;
+  VALUE rb_color;
+  Imlib_Color_Range range;
+  double angle;
 
   Check_Type(rb_x, T_FIXNUM);
   Check_Type(rb_y, T_FIXNUM);
@@ -553,25 +602,21 @@ static VALUE rszr_image_rectangle_bang(VALUE self, VALUE rb_color, VALUE rb_x, V
   int w = NUM2INT(rb_w);
   int h = NUM2INT(rb_h);
 
+  rb_gradient = rb_funcall(rb_fill, rb_intern("gradient"), 0);
+  rb_color = rb_funcall(rb_fill, rb_intern("color"), 0);
+  
   Data_Get_Struct(self, rszr_image_handle, handle);
-
   imlib_context_set_image(handle->image);
-  rszr_image_color_set(rb_color);
-  imlib_image_fill_rectangle(x, y, w, h);
-
-  return self;
-}
-
 
-static VALUE rszr_image_fill_bang(VALUE self, VALUE rb_color)
-{
-  rszr_image_handle * handle;
-
-  Data_Get_Struct(self, rszr_image_handle, handle);
-
-  imlib_context_set_image(handle->image);
-  rszr_image_color_set(rb_color);
-  imlib_image_fill_rectangle(0, 0, imlib_image_get_width(), imlib_image_get_height());
+  if (!NIL_P(rb_gradient)) {
+    angle = NUM2DBL(rb_funcall(rb_fill, rb_intern("angle"), 0));
+    range = rszr_image_init_color_range(rb_gradient);
+    imlib_image_fill_color_range_rectangle(x, y, w, h, angle);
+    imlib_free_color_range();
+  } else if (!NIL_P(rb_color)) {
+    rszr_image_color_set(rb_color);
+    imlib_image_fill_rectangle(x, y, w, h);
+  }
 
   return self;
 }
@@ -614,6 +659,12 @@ static VALUE rszr_image__save(VALUE self, VALUE rb_path, VALUE rb_format, VALUE
 void Init_rszr_image()
 {
   cImage = rb_define_class_under(mRszr, "Image", rb_cObject);
+
+  cColorBase = rb_path2class("Rszr::Color::Base");
+  cColorGradient = rb_path2class("Rszr::Color::Gradient");
+  cColorPoint = rb_path2class("Rszr::Color::Point");
+  cFill = rb_path2class("Rszr::Fill");
+
   rb_define_alloc_func(cImage, rszr_image_s_allocate);
 
   // Class methods
@@ -626,15 +677,13 @@ void Init_rszr_image()
   rb_define_method(cImage, "filter!",     rszr_image_filter_bang, 1);
   rb_define_method(cImage, "flop!",       rszr_image_flop_bang, 0);
   rb_define_method(cImage, "flip!",       rszr_image_flip_bang, 0);
-  rb_define_method(cImage, "rectangle!",  rszr_image_rectangle_bang, 5);
-  rb_define_method(cImage, "fill!",       rszr_image_fill_bang, 1);
   
   rb_define_method(cImage, "alpha",   rszr_image_alpha_get, 0);
   rb_define_method(cImage, "alpha=",  rszr_image_alpha_set, 1);
   
   rb_define_protected_method(cImage, "_format",  rszr_image__format_get, 0);
   rb_define_protected_method(cImage, "_format=", rszr_image__format_set, 1);
-  
+
   rb_define_private_method(cImage, "_initialize", rszr_image__initialize, 2);
   rb_define_private_method(cImage, "_resize",     rszr_image__resize, 7);
   rb_define_private_method(cImage, "_crop",       rszr_image__crop, 5);
@@ -643,6 +692,8 @@ void Init_rszr_image()
   rb_define_private_method(cImage, "_sharpen!",   rszr_image__sharpen_bang, 1);
   rb_define_private_method(cImage, "_pixel",      rszr_image__pixel_get, 2);
   rb_define_private_method(cImage, "_blend",      rszr_image__blend, 11);
+  rb_define_private_method(cImage, "_rectangle!", rszr_image__rectangle_bang, 5);
+
   rb_define_private_method(cImage, "_save",       rszr_image__save, 4);
 }
 
diff --git a/lib/rszr.rb b/lib/rszr.rb
index 8a77144..1b43730 100644
--- a/lib/rszr.rb
+++ b/lib/rszr.rb
@@ -3,13 +3,14 @@
 require 'tempfile'
 require 'stringio'
 
-require 'rszr/rszr'
 require 'rszr/version'
 require 'rszr/stream'
 require 'rszr/identification'
 require 'rszr/orientation'
 require 'rszr/buffered'
 require 'rszr/color'
+require 'rszr/fill'
+require 'rszr/rszr'
 require 'rszr/image'
 
 module Rszr
diff --git a/lib/rszr/color.rb b/lib/rszr/color.rb
index 3f8f866..32afb8d 100644
--- a/lib/rszr/color.rb
+++ b/lib/rszr/color.rb
@@ -1,66 +1,12 @@
+require_relative 'color/base'
+require_relative 'color/rgba'
+require_relative 'color/cmya'
+require_relative 'color/point'
+require_relative 'color/gradient'
+
 module Rszr
   module Color
 
-    class Base
-      attr_reader :alpha
-    end
-
-    class RGBA < Base
-      attr_reader :red, :green, :blue
-
-      def initialize(red, green, blue, alpha = 255)
-        if red < 0 || red > 255 || green < 0 || green > 255 || blue < 0 || blue > 255 || alpha < 0 || alpha > 255
-          raise ArgumentError, 'color out of range'
-        end
-        @red, @green, @blue, @alpha = red, green, blue, alpha
-      end
-
-      def cyan
-        255 - red
-      end
-
-      def magenta
-        255 - green
-      end
-
-      def yellow
-        255 - blue
-      end
-
-      def to_i(alpha: true)
-        i = red.to_i << 24 | green.to_i << 16 | blue.to_i << 8 | alpha.to_i
-        alpha ? i : i >> 8
-      end
-
-      def to_hex(rgb: false)
-        "%0#{rgb ? 6 : 8}x" % to_i(rgb: rgb)
-      end
-    end
-
-    class CMYA < Base
-      attr_reader :cyan, :magenta, :yellow
-
-      def initialize(cyan, magenta, yellow, alpha = 255)
-        if cyan < 0 || cyan > 255 || magenta < 0 || magenta > 255 || yellow < 0 || yellow > 255 || alpha < 0 || alpha > 255
-          raise ArgumentError, 'color out of range'
-        end
-        @cyan, @magenta, @yellow = cyan, magenta, yellow
-      end
-
-      def red
-        255 - cyan
-      end
-
-      def green
-        255 - magenta
-      end
-
-      def blue
-        255 - yellow
-      end
-
-    end
-
     Transparent = RGBA.new(0, 0, 0, 0)
     White = RGBA.new(255,255,255)
     Black = RGBA.new(0, 0, 0)
diff --git a/lib/rszr/color/base.rb b/lib/rszr/color/base.rb
new file mode 100644
index 0000000..1d320a5
--- /dev/null
+++ b/lib/rszr/color/base.rb
@@ -0,0 +1,21 @@
+module Rszr
+  module Color
+
+    class Base
+      attr_reader :alpha
+
+      def rgba
+        [red, green, blue, alpha]
+      end
+
+      def cmya
+        [cyan, magenta, yellow, alpha]
+      end
+
+      def to_fill(*)
+        Fill.new(color: self)
+      end
+    end
+
+  end
+end
diff --git a/lib/rszr/color/cmya.rb b/lib/rszr/color/cmya.rb
new file mode 100644
index 0000000..dc23dc3
--- /dev/null
+++ b/lib/rszr/color/cmya.rb
@@ -0,0 +1,29 @@
+module Rszr
+  module Color
+
+    class CMYA < Base
+      attr_reader :cyan, :magenta, :yellow
+
+      def initialize(cyan, magenta, yellow, alpha = 255)
+        if cyan < 0 || cyan > 255 || magenta < 0 || magenta > 255 || yellow < 0 || yellow > 255 || alpha < 0 || alpha > 255
+          raise ArgumentError, 'color out of range'
+        end
+        @cyan, @magenta, @yellow = cyan, magenta, yellow
+      end
+
+      def red
+        255 - cyan
+      end
+
+      def green
+        255 - magenta
+      end
+
+      def blue
+        255 - yellow
+      end
+
+    end
+
+  end
+end
diff --git a/lib/rszr/color/gradient.rb b/lib/rszr/color/gradient.rb
new file mode 100644
index 0000000..705d358
--- /dev/null
+++ b/lib/rszr/color/gradient.rb
@@ -0,0 +1,40 @@
+module Rszr
+  module Color
+
+    class Gradient
+      attr_reader :points
+
+      def initialize(*args)
+        @points = []
+        points = args.last.is_a?(Hash) ? args.pop.dup : {}
+        args.each { |point| self << point }
+        points.each { |pos, color| point(pos, color) }
+        yield self if block_given?
+      end
+
+      def initialize_dup(other) # :nodoc:
+        @points = other.points.map(&:dup)
+      end
+
+      def <<(position, red = nil, green = nil, blue= nil, alpha = 255)
+        point = if red.is_a?(Point)
+          red
+        elsif red.is_a?(Color::Base)
+          Point.new(position, red)
+        else
+          Point.new(position, RGBA.new(red, green, blue, alpha))
+        end
+        points << point
+        points.sort!
+      end
+
+      alias_method :point, :<<
+      
+      def to_fill(angle = 0)
+        Fill.new(gradient: self, angle: angle)
+      end
+
+    end
+
+  end
+end
diff --git a/lib/rszr/color/point.rb b/lib/rszr/color/point.rb
new file mode 100644
index 0000000..9ffc9a0
--- /dev/null
+++ b/lib/rszr/color/point.rb
@@ -0,0 +1,29 @@
+module Rszr
+  module Color
+
+    class Point
+      attr_reader :position, :color
+
+      class << self
+        def prgba(position, red, green, blue, alpha = 255)
+          new(position, RGBA.new(red, green, blue, alpha))
+        end
+      end
+
+      def initialize(position, color)
+        raise ArgumentError, 'position must be within 0..1' unless (0..1).cover?(position)
+        raise ArgumentError, 'color must be a Rszr::Color::Base' unless color.is_a?(Rszr::Color::Base)
+        @position, @color = position, color
+      end
+
+      def <=>(other)
+        position <=> other.position
+      end
+
+      def prgba
+        [position, *color.rgba]
+      end
+    end
+
+  end
+end
diff --git a/lib/rszr/color/rgba.rb b/lib/rszr/color/rgba.rb
new file mode 100644
index 0000000..3fc22e7
--- /dev/null
+++ b/lib/rszr/color/rgba.rb
@@ -0,0 +1,44 @@
+module Rszr
+  module Color
+    
+    class << self
+      def rgba(red, green, blue, alpha = 255)
+        RGBA.new(red, green, blue, alpha)
+      end
+    end
+
+    class RGBA < Base
+      attr_reader :red, :green, :blue
+
+      def initialize(red, green, blue, alpha = 255)
+        if red < 0 || red > 255 || green < 0 || green > 255 || blue < 0 || blue > 255 || alpha < 0 || alpha > 255
+          raise ArgumentError, 'color out of range'
+        end
+        @red, @green, @blue, @alpha = red, green, blue, alpha
+      end
+
+      def cyan
+        255 - red
+      end
+
+      def magenta
+        255 - green
+      end
+
+      def yellow
+        255 - blue
+      end
+
+      def to_i(alpha: true)
+        i = red.to_i << 24 | green.to_i << 16 | blue.to_i << 8 | alpha.to_i
+        alpha ? i : i >> 8
+      end
+
+      def to_hex(rgb: false)
+        "%0#{rgb ? 6 : 8}x" % to_i(rgb: rgb)
+      end
+
+    end
+
+  end
+end
diff --git a/lib/rszr/fill.rb b/lib/rszr/fill.rb
new file mode 100644
index 0000000..aedaa7e
--- /dev/null
+++ b/lib/rszr/fill.rb
@@ -0,0 +1,21 @@
+module Rszr
+  class Fill
+    attr_reader :color, :gradient, :angle
+
+    def initialize(color: nil, gradient: nil, angle: 0)
+      if gradient
+        @gradient = gradient
+        @angle = angle || 0
+      elsif color
+        @color = color
+      else
+        raise ArgumentError, 'incomplete fill definition'
+      end
+    end
+
+    def to_fill(*)
+      self
+    end
+
+  end
+end
diff --git a/lib/rszr/image.rb b/lib/rszr/image.rb
index 3f1c535..45f3b78 100644
--- a/lib/rszr/image.rb
+++ b/lib/rszr/image.rb
@@ -148,17 +148,36 @@ def gamma(*args, **opts)
         dup.gamma!(*args, **opts)
       end
       
+      # bang?
       def blend(image, mode: :copy)
         raise ArgumentError, "mode must be one of #{BLENDING_MODES.map(&:to_s).join(', ')}" unless BLENDING_MODES.include?(mode)
         _blend(image, true, BLENDING_MODES.index(mode), 0, 0, image.width, image.height, 0, 0, image.width, image.height)
       end
+      
+      def rectangle!(coloring, x, y, w, h)
+        raise ArgumentError, "coloring must respond to to_fill" unless coloring.respond_to?(:to_fill)
+        _rectangle!(coloring.to_fill, x, y, w, h)
+      end
+      
+      def rectangle(*args, **opts)
+        dup.rectangle!(*args, **opts)
+      end
+      
+      def fill!(coloring)
+        raise ArgumentError, "coloring must respond to to_fill" unless coloring.respond_to?(:to_fill)
+        rectangle!(coloring, 0, 0, width, height)
+      end
+      
+      def fill(*args, **opts)
+        dup.fill(*args, **opts)
+      end
     end
     
     include Transformations
 
     def initialize(width, height, alpha: false, background: nil)
       raise ArgumentError, 'illegal image dimensions' if width < 1 || width > 32766 || height < 1 || height > 32766
-      raise ArgumentError, 'background must descend from Rszr::Color::Base' if background && !(background.class < Color::Base)
+      raise ArgumentError, 'background must respond to to_fill' if background && !(background.respond_to?(:to_fill))
       _initialize(width, height).tap do |image|
         image.alpha = alpha
         image.fill!(background) if background

From bef9a4f4a162cc8e54bd76a99e687403c6539cf3 Mon Sep 17 00:00:00 2001
From: Matthias Grosser <mtgrosser@gmx.net>
Date: Tue, 29 Mar 2022 13:03:57 +0200
Subject: [PATCH 4/4] Hex color code support

---
 CHANGELOG.md               |  8 +++--
 README.md                  | 70 +++++++++++++++++++++++++++++++++++---
 lib/rszr/color/base.rb     |  4 +++
 lib/rszr/color/gradient.rb |  2 ++
 lib/rszr/color/rgba.rb     | 18 ++++++++--
 lib/rszr/image.rb          |  9 +++--
 spec/rszr_spec.rb          |  4 +--
 7 files changed, 101 insertions(+), 14 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0547431..d15eeb6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,11 +1,15 @@
 ## Rszr 1.3.0 (unreleased)
 
-* Fix saving without extension (@mantas)
 * Alpha channel control
 * Background initialization
-* Image blending
+* Image blending / watermarking
 * Rectangle and image fills
 * Color gradients
+* Hex color codes always prefixed by "#"
+
+## Rszr 1.2.1 (Mar 22, 2022)
+
+* Fix saving without extension (@mantas)
 
 ## Rszr 1.2.0 (Mar 11, 2022)
 
diff --git a/README.md b/README.md
index 36ec4c5..59bea1e 100644
--- a/README.md
+++ b/README.md
@@ -60,9 +60,10 @@ image.width => 400
 image.height => 300
 image.dimensions => [400, 300]
 image.format => "jpeg"
+image.alpha? => false
 image[0, 0] => <Rszr::Color::RGBA @red=38, @green=115, @blue=141, @alpha=255>
-image[0, 0].to_hex => "26738dff"
-image[0, 0].to_hex(rgb: true) => "26738d"
+image[0, 0].to_hex => "#26738dff"
+image[0, 0].to_hex(alpha: false) => "#26738d"
 ```
 
 ### Transformations
@@ -141,14 +142,75 @@ end
 image.rectangle!(gradient.to_fill(45), 100, 100, 300, 300)
 ```
 
-### Watermarking
+### Colors
+
+```ruby
+# pre-defined colors
+Rszr::Color::White
+Rszr::Color::Black
+Rszr::Color::Transparent
+
+# RGB
+color = Rszr::Color.rgba(255, 250, 50)
+color.red => 255
+color.green => 250
+color.blue => 50
+color.alpha => 255
+color.cyan => 0
+color.magenta => 5
+color.yellow => 205
+
+# RGBA
+Rszr::Color.rgba(255, 250, 50, 255)
+
+# CMY
+Rszr::Color.cmya(0, 5, 205)
+
+# CMYA
+Rszr::Color.cmya(0, 5, 205, 255)
+```
+
+### Color gradients
+
+```ruby
+# three-color linear gradient with changing opacity
+gradient = Rszr::Color::Gradient.new do |g|
+  g.point 0, 255, 250, 205, 50
+  g.point 0.5, 135, 206, 250
+  g.point 1, Rszr::Color::White
+end
+
+# alternative syntax
+gradient = Rszr::Color::Gradient.new(0 => "#fffacd32", 0.5 => "#87cefa", 1 => "#fff")
+
+# generate fill with 45° angle
+fill = gradient.to_fill(45)
+
+# use as image background
+image = Rszr::Image.new(500, 500, background: fill)
+```
+
+### Watermarking and image blending
 
 ```ruby
 # load logo
 logo = Rszr::Image.load('logo.png')
 
+# load image
+image = Rszr::Image.load('image.jpg')
+
+# enable alpha channel
+image.alpha = true
+
 # blend it onto the image at position (10, 10)
-image.blend(logo, 10, 10)
+image.blend!(logo, 10, 10)
+
+# blending modes:
+# - copy (default)
+# - add
+# - subtract
+# - reshade
+image.blend(logo, 10, 10, mode: :subtract)
 ```
 
 ### Filters
diff --git a/lib/rszr/color/base.rb b/lib/rszr/color/base.rb
index 1d320a5..bc0d070 100644
--- a/lib/rszr/color/base.rb
+++ b/lib/rszr/color/base.rb
@@ -12,6 +12,10 @@ def cmya
         [cyan, magenta, yellow, alpha]
       end
 
+      def ==(other)
+        other.is_a?(Base) && rgba == other.rgba
+      end
+
       def to_fill(*)
         Fill.new(color: self)
       end
diff --git a/lib/rszr/color/gradient.rb b/lib/rszr/color/gradient.rb
index 705d358..d022b94 100644
--- a/lib/rszr/color/gradient.rb
+++ b/lib/rszr/color/gradient.rb
@@ -21,6 +21,8 @@ def <<(position, red = nil, green = nil, blue= nil, alpha = 255)
           red
         elsif red.is_a?(Color::Base)
           Point.new(position, red)
+        elsif red.is_a?(String) && red.start_with?('#')
+          Point.new(position, Color.hex(red))
         else
           Point.new(position, RGBA.new(red, green, blue, alpha))
         end
diff --git a/lib/rszr/color/rgba.rb b/lib/rszr/color/rgba.rb
index 3fc22e7..9b41245 100644
--- a/lib/rszr/color/rgba.rb
+++ b/lib/rszr/color/rgba.rb
@@ -5,6 +5,18 @@ class << self
       def rgba(red, green, blue, alpha = 255)
         RGBA.new(red, green, blue, alpha)
       end
+
+      def hex(str)
+        str = str[1..-1] if str.start_with?('#')
+        case str.size
+        when 3, 4 then hex(str.chars.map { |c| c * 2 }.join)
+        when 6 then hex("#{str}ff")
+        when 8
+          rgba(*str.scan(/../).map(&:hex))
+        else
+          raise ArgumentError, 'invalid color code'
+        end
+      end
     end
 
     class RGBA < Base
@@ -30,12 +42,12 @@ def yellow
       end
 
       def to_i(alpha: true)
-        i = red.to_i << 24 | green.to_i << 16 | blue.to_i << 8 | alpha.to_i
+        i = red.to_i << 24 | green.to_i << 16 | blue.to_i << 8 | self.alpha.to_i
         alpha ? i : i >> 8
       end
 
-      def to_hex(rgb: false)
-        "%0#{rgb ? 6 : 8}x" % to_i(rgb: rgb)
+      def to_hex(alpha: true)
+        "#%0#{alpha ? 8 : 6}x" % to_i(alpha: alpha)
       end
 
     end
diff --git a/lib/rszr/image.rb b/lib/rszr/image.rb
index 45f3b78..287c56d 100644
--- a/lib/rszr/image.rb
+++ b/lib/rszr/image.rb
@@ -148,10 +148,13 @@ def gamma(*args, **opts)
         dup.gamma!(*args, **opts)
       end
       
-      # bang?
-      def blend(image, mode: :copy)
+      def blend!(image, x, y, mode: :copy)
         raise ArgumentError, "mode must be one of #{BLENDING_MODES.map(&:to_s).join(', ')}" unless BLENDING_MODES.include?(mode)
-        _blend(image, true, BLENDING_MODES.index(mode), 0, 0, image.width, image.height, 0, 0, image.width, image.height)
+        _blend(image, true, BLENDING_MODES.index(mode), 0, 0, image.width, image.height, x, y, image.width, image.height)
+      end
+      
+      def blend(*args, **opts)
+        dup.blend!(*args, **opts)
       end
       
       def rectangle!(coloring, x, y, w, h)
diff --git a/spec/rszr_spec.rb b/spec/rszr_spec.rb
index e5db69d..da288a8 100644
--- a/spec/rszr_spec.rb
+++ b/spec/rszr_spec.rb
@@ -53,11 +53,11 @@
     end
     
     it 'provide pixel RGBA value' do
-      expect(@image[0, 0].to_hex).to eq('4c5c6cff')
+      expect(@image[0, 0].to_hex).to eq('#4c5c6cff')
     end
     
     it 'provide pixel RGB value' do
-      expect(@image[0, 0].to_hex(rgb: true)).to eq('4c5c6c')
+      expect(@image[0, 0].to_hex(alpha: false)).to eq('#4c5c6c')
     end
     
     it 'return nil if pixel out of bounds' do