Added support for linear and radial gradients

Closes #29

spec/graphics/cairo_context_wrapper_spec.rb

@@ -0,0 +1,75 @@
+require 'spec_helper'
+require 'squib/graphics/cairo_context_wrapper'
+
+describe Squib::Graphics::CairoContextWrapper do
+
+  let(:cairo) { double(Cairo::Context) }
+  subject     { Squib::Graphics::CairoContextWrapper.new(cairo) }
+
+  it 'passes on colors as normal' do
+    expect(cairo).to receive(:set_source_color).with('blue')
+    subject.set_source_squibcolor('blue')
+  end
+
+  it 'passes on color symbols as normal' do
+    expect(cairo).to receive(:set_source_color).with(:blue)
+    subject.set_source_squibcolor(:blue)
+  end
+
+  it 'passes on color hashes' do
+    expect(cairo).to receive(:set_source_color)
+      .with('#aabbccdd')
+    subject.set_source_squibcolor('#aabbccdd')
+  end
+
+  context 'regex variations for linear gradients' do
+    before(:each) do
+      dbl = double(Cairo::LinearPattern)
+      expect(Cairo::LinearPattern).to receive(:new).with(1,2,3,4).and_return(dbl)
+      expect(dbl).to   receive(:add_color_stop).with(0.0, 'blue')
+      expect(dbl).to   receive(:add_color_stop).with(1.0, 'red')
+      expect(cairo).to receive(:set_source).with(dbl)
+    end
+
+    it('handles no decimals'  ) { subject.set_source_squibcolor('(1,2) (3,4) blue@0 red@1') }
+    it('handles decimals'     ) { subject.set_source_squibcolor('(1.0,2.0) (3.0,4.0) blue@0 red@1') }
+    it('handles no whitespace') { subject.set_source_squibcolor('(1,2)(3,4)blue@0red@1') }
+    it('handles whitespace'   ) { subject.set_source_squibcolor('  (  1  ,  2  )  ( 3  ,  4  )  blue@0   red@1   ') }
+  end
+
+  context 'regex variations for radial gradients' do
+    before(:each) do
+      dbl = double(Cairo::RadialPattern)
+      expect(Cairo::RadialPattern).to receive(:new).with(1,2,5,3,4,6).and_return(dbl)
+      expect(dbl).to   receive(:add_color_stop).with(0.0, 'blue')
+      expect(dbl).to   receive(:add_color_stop).with(1.0, 'red')
+      expect(cairo).to receive(:set_source).with(dbl)
+    end
+
+    it('handles no decimals'  ) { subject.set_source_squibcolor('(1,2,5) (3,4,6) blue@0 red@1') }
+    it('handles decimals'     ) { subject.set_source_squibcolor('(1.0,2.0,5.0) (3.0,4.0,6.0) blue@0 red@1') }
+    it('handles no whitespace') { subject.set_source_squibcolor('(1,2,5)(3,4,6)blue@0red@1') }
+    it('handles whitespace'   ) { subject.set_source_squibcolor('  (  1  ,  2  , 5 )  ( 3  ,  4 , 6 )  blue@0   red@1   ') }
+  end
+
+  context 'regex handles hash notation' do
+    it 'on radial patterns' do
+      dbl = double(Cairo::RadialPattern)
+      expect(Cairo::RadialPattern).to receive(:new).with(1,2,5,3,4,6).and_return(dbl)
+      expect(dbl).to   receive(:add_color_stop).with(0.0, '#def')
+      expect(dbl).to   receive(:add_color_stop).with(1.0, '#112233')
+      expect(cairo).to receive(:set_source).with(dbl)
+      subject.set_source_squibcolor('(1,2,5) (3,4,6) #def@0 #112233@1')
+    end
+
+    it 'on linear patterns' do
+      dbl = double(Cairo::LinearPattern)
+      expect(Cairo::LinearPattern).to receive(:new).with(1,2,3,4).and_return(dbl)
+      expect(dbl).to   receive(:add_color_stop).with(0.0, '#def')
+      expect(dbl).to   receive(:add_color_stop).with(1.0, '#112233')
+      expect(cairo).to receive(:set_source).with(dbl)
+      subject.set_source_squibcolor('(1,2) (3,4) #def@0 #112233@1')
+    end
+  end
+
+end