Add text blending support

Introduce constants for bit mask and use them instead of shifts.

Add test cases to check remaining code sections to really panic if
the provided text is not parsable.

Add test case to make sure that adding a color to an already styled
text with emphasis like bold or italic does apply the color correctly
without corrupting the existing settings.

Add `Blend` style option that allows for color blending instead of
overwritting the existing color.

bunt.go

@@ -24,6 +24,15 @@ import (
 	"github.com/gonvenience/term"
 )
 
+// Internal bit mask to mark feature states, e.g. foreground coloring
+const (
+	fgMask        = 0x1
+	bgMask        = 0x2
+	boldMask      = 0x4
+	italicMask    = 0x8
+	underlineMask = 0x10
+)
+
 // ColorSetting defines the coloring setting to be used
 var ColorSetting = AUTO
 

colors_test.go

@@ -0,0 +1,209 @@
+// Copyright © 2019 The Homeport Team
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package bunt_test
+
+import (
+	"fmt"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+
+	. "github.com/gonvenience/bunt"
+)
+
+var _ = Describe("color specific tests", func() {
+	Context("fallback to 4 bit colors for non true color terminals", func() {
+		BeforeEach(func() {
+			ColorSetting = ON
+			TrueColorSetting = OFF
+		})
+
+		AfterEach(func() {
+			ColorSetting = AUTO
+			TrueColorSetting = AUTO
+		})
+
+		var (
+			f1 = func(color string) string {
+				input := fmt.Sprintf("%s{%s}", color, "text")
+				result, err := ParseString(input, ProcessTextAnnotations())
+				Expect(err).ToNot(HaveOccurred())
+				Expect(result).ToNot(BeNil())
+				return result.String()
+			}
+
+			f2 = func(color uint8) string {
+				return fmt.Sprintf("\x1b[%dm%s\x1b[0m", color, "text")
+			}
+		)
+
+		It("should find a suitable 4 bit equivalent color for both foreground and background", func() {
+			input := "Example: \x1b[38;2;133;247;7mforeground\x1b[0m, and \x1b[48;2;133;247;7mbackground\x1b[0m."
+			result, err := ParseString(input)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(result).ToNot(BeNil())
+			Expect(result.String()).To(BeEquivalentTo("Example: \x1b[92mforeground\x1b[0m, and \x1b[102mbackground\x1b[0m."))
+		})
+
+		It("should match known combinations of a true color to a 4 bit color", func() {
+			Expect(f1("Black")).To(BeEquivalentTo(f2(30)))                // Black matches Black (#30)
+			Expect(f1("Brown")).To(BeEquivalentTo(f2(31)))                // Brown matches Red (#31)
+			Expect(f1("DarkRed")).To(BeEquivalentTo(f2(31)))              // DarkRed matches Red (#31)
+			Expect(f1("FireBrick")).To(BeEquivalentTo(f2(31)))            // FireBrick matches Red (#31)
+			Expect(f1("Maroon")).To(BeEquivalentTo(f2(31)))               // Maroon matches Red (#31)
+			Expect(f1("SaddleBrown")).To(BeEquivalentTo(f2(31)))          // SaddleBrown matches Red (#31)
+			Expect(f1("Sienna")).To(BeEquivalentTo(f2(31)))               // Sienna matches Red (#31)
+			Expect(f1("DarkGreen")).To(BeEquivalentTo(f2(32)))            // DarkGreen matches Green (#32)
+			Expect(f1("DarkSeaGreen")).To(BeEquivalentTo(f2(32)))         // DarkSeaGreen matches Green (#32)
+			Expect(f1("ForestGreen")).To(BeEquivalentTo(f2(32)))          // ForestGreen matches Green (#32)
+			Expect(f1("Green")).To(BeEquivalentTo(f2(32)))                // Green matches Green (#32)
+			Expect(f1("LimeGreen")).To(BeEquivalentTo(f2(32)))            // LimeGreen matches Green (#32)
+			Expect(f1("MediumSeaGreen")).To(BeEquivalentTo(f2(32)))       // MediumSeaGreen matches Green (#32)
+			Expect(f1("Olive")).To(BeEquivalentTo(f2(32)))                // Olive matches Green (#32)
+			Expect(f1("OliveDrab")).To(BeEquivalentTo(f2(32)))            // OliveDrab matches Green (#32)
+			Expect(f1("SeaGreen")).To(BeEquivalentTo(f2(32)))             // SeaGreen matches Green (#32)
+			Expect(f1("Gold")).To(BeEquivalentTo(f2(33)))                 // Gold matches Yellow (#33)
+			Expect(f1("Yellow")).To(BeEquivalentTo(f2(33)))               // Yellow matches Yellow (#33)
+			Expect(f1("Blue")).To(BeEquivalentTo(f2(34)))                 // Blue matches Blue (#34)
+			Expect(f1("DarkBlue")).To(BeEquivalentTo(f2(34)))             // DarkBlue matches Blue (#34)
+			Expect(f1("DarkSlateBlue")).To(BeEquivalentTo(f2(34)))        // DarkSlateBlue matches Blue (#34)
+			Expect(f1("Indigo")).To(BeEquivalentTo(f2(34)))               // Indigo matches Blue (#34)
+			Expect(f1("MediumBlue")).To(BeEquivalentTo(f2(34)))           // MediumBlue matches Blue (#34)
+			Expect(f1("MidnightBlue")).To(BeEquivalentTo(f2(34)))         // MidnightBlue matches Blue (#34)
+			Expect(f1("Navy")).To(BeEquivalentTo(f2(34)))                 // Navy matches Blue (#34)
+			Expect(f1("BlueViolet")).To(BeEquivalentTo(f2(35)))           // BlueViolet matches Magenta (#35)
+			Expect(f1("DarkMagenta")).To(BeEquivalentTo(f2(35)))          // DarkMagenta matches Magenta (#35)
+			Expect(f1("DarkOrchid")).To(BeEquivalentTo(f2(35)))           // DarkOrchid matches Magenta (#35)
+			Expect(f1("DarkViolet")).To(BeEquivalentTo(f2(35)))           // DarkViolet matches Magenta (#35)
+			Expect(f1("MediumVioletRed")).To(BeEquivalentTo(f2(35)))      // MediumVioletRed matches Magenta (#35)
+			Expect(f1("Purple")).To(BeEquivalentTo(f2(35)))               // Purple matches Magenta (#35)
+			Expect(f1("CadetBlue")).To(BeEquivalentTo(f2(36)))            // CadetBlue matches Cyan (#36)
+			Expect(f1("DarkCyan")).To(BeEquivalentTo(f2(36)))             // DarkCyan matches Cyan (#36)
+			Expect(f1("DarkTurquoise")).To(BeEquivalentTo(f2(36)))        // DarkTurquoise matches Cyan (#36)
+			Expect(f1("DeepSkyBlue")).To(BeEquivalentTo(f2(36)))          // DeepSkyBlue matches Cyan (#36)
+			Expect(f1("LightSeaGreen")).To(BeEquivalentTo(f2(36)))        // LightSeaGreen matches Cyan (#36)
+			Expect(f1("MediumAquamarine")).To(BeEquivalentTo(f2(36)))     // MediumAquamarine matches Cyan (#36)
+			Expect(f1("Teal")).To(BeEquivalentTo(f2(36)))                 // Teal matches Cyan (#36)
+			Expect(f1("BurlyWood")).To(BeEquivalentTo(f2(37)))            // BurlyWood matches White (#37)
+			Expect(f1("DarkGoldenrod")).To(BeEquivalentTo(f2(37)))        // DarkGoldenrod matches White (#37)
+			Expect(f1("DarkGray")).To(BeEquivalentTo(f2(37)))             // DarkGray matches White (#37)
+			Expect(f1("Gray")).To(BeEquivalentTo(f2(37)))                 // Gray matches White (#37)
+			Expect(f1("LightPink")).To(BeEquivalentTo(f2(37)))            // LightPink matches White (#37)
+			Expect(f1("LightSkyBlue")).To(BeEquivalentTo(f2(37)))         // LightSkyBlue matches White (#37)
+			Expect(f1("LightSlateGray")).To(BeEquivalentTo(f2(37)))       // LightSlateGray matches White (#37)
+			Expect(f1("LightSteelBlue")).To(BeEquivalentTo(f2(37)))       // LightSteelBlue matches White (#37)
+			Expect(f1("Pink")).To(BeEquivalentTo(f2(37)))                 // Pink matches White (#37)
+			Expect(f1("RosyBrown")).To(BeEquivalentTo(f2(37)))            // RosyBrown matches White (#37)
+			Expect(f1("SandyBrown")).To(BeEquivalentTo(f2(37)))           // SandyBrown matches White (#37)
+			Expect(f1("Silver")).To(BeEquivalentTo(f2(37)))               // Silver matches White (#37)
+			Expect(f1("Tan")).To(BeEquivalentTo(f2(37)))                  // Tan matches White (#37)
+			Expect(f1("Thistle")).To(BeEquivalentTo(f2(37)))              // Thistle matches White (#37)
+			Expect(f1("DarkOliveGreen")).To(BeEquivalentTo(f2(90)))       // DarkOliveGreen matches BrightBlack (#90)
+			Expect(f1("DarkSlateGray")).To(BeEquivalentTo(f2(90)))        // DarkSlateGray matches BrightBlack (#90)
+			Expect(f1("DimGray")).To(BeEquivalentTo(f2(90)))              // DimGray matches BrightBlack (#90)
+			Expect(f1("Chocolate")).To(BeEquivalentTo(f2(91)))            // Chocolate matches BrightRed (#91)
+			Expect(f1("Coral")).To(BeEquivalentTo(f2(91)))                // Coral matches BrightRed (#91)
+			Expect(f1("Crimson")).To(BeEquivalentTo(f2(91)))              // Crimson matches BrightRed (#91)
+			Expect(f1("DarkOrange")).To(BeEquivalentTo(f2(91)))           // DarkOrange matches BrightRed (#91)
+			Expect(f1("DarkSalmon")).To(BeEquivalentTo(f2(91)))           // DarkSalmon matches BrightRed (#91)
+			Expect(f1("IndianRed")).To(BeEquivalentTo(f2(91)))            // IndianRed matches BrightRed (#91)
+			Expect(f1("LightCoral")).To(BeEquivalentTo(f2(91)))           // LightCoral matches BrightRed (#91)
+			Expect(f1("LightSalmon")).To(BeEquivalentTo(f2(91)))          // LightSalmon matches BrightRed (#91)
+			Expect(f1("OrangeRed")).To(BeEquivalentTo(f2(91)))            // OrangeRed matches BrightRed (#91)
+			Expect(f1("PaleVioletRed")).To(BeEquivalentTo(f2(91)))        // PaleVioletRed matches BrightRed (#91)
+			Expect(f1("Peru")).To(BeEquivalentTo(f2(91)))                 // Peru matches BrightRed (#91)
+			Expect(f1("Red")).To(BeEquivalentTo(f2(91)))                  // Red matches BrightRed (#91)
+			Expect(f1("Salmon")).To(BeEquivalentTo(f2(91)))               // Salmon matches BrightRed (#91)
+			Expect(f1("Tomato")).To(BeEquivalentTo(f2(91)))               // Tomato matches BrightRed (#91)
+			Expect(f1("Chartreuse")).To(BeEquivalentTo(f2(92)))           // Chartreuse matches BrightGreen (#92)
+			Expect(f1("GreenYellow")).To(BeEquivalentTo(f2(92)))          // GreenYellow matches BrightGreen (#92)
+			Expect(f1("LawnGreen")).To(BeEquivalentTo(f2(92)))            // LawnGreen matches BrightGreen (#92)
+			Expect(f1("LightGreen")).To(BeEquivalentTo(f2(92)))           // LightGreen matches BrightGreen (#92)
+			Expect(f1("Lime")).To(BeEquivalentTo(f2(92)))                 // Lime matches BrightGreen (#92)
+			Expect(f1("MediumSpringGreen")).To(BeEquivalentTo(f2(92)))    // MediumSpringGreen matches BrightGreen (#92)
+			Expect(f1("PaleGreen")).To(BeEquivalentTo(f2(92)))            // PaleGreen matches BrightGreen (#92)
+			Expect(f1("SpringGreen")).To(BeEquivalentTo(f2(92)))          // SpringGreen matches BrightGreen (#92)
+			Expect(f1("YellowGreen")).To(BeEquivalentTo(f2(92)))          // YellowGreen matches BrightGreen (#92)
+			Expect(f1("DarkKhaki")).To(BeEquivalentTo(f2(93)))            // DarkKhaki matches BrightYellow (#93)
+			Expect(f1("Goldenrod")).To(BeEquivalentTo(f2(93)))            // Goldenrod matches BrightYellow (#93)
+			Expect(f1("Khaki")).To(BeEquivalentTo(f2(93)))                // Khaki matches BrightYellow (#93)
+			Expect(f1("Orange")).To(BeEquivalentTo(f2(93)))               // Orange matches BrightYellow (#93)
+			Expect(f1("PaleGoldenrod")).To(BeEquivalentTo(f2(93)))        // PaleGoldenrod matches BrightYellow (#93)
+			Expect(f1("CornflowerBlue")).To(BeEquivalentTo(f2(94)))       // CornflowerBlue matches BrightBlue (#94)
+			Expect(f1("DodgerBlue")).To(BeEquivalentTo(f2(94)))           // DodgerBlue matches BrightBlue (#94)
+			Expect(f1("MediumPurple")).To(BeEquivalentTo(f2(94)))         // MediumPurple matches BrightBlue (#94)
+			Expect(f1("MediumSlateBlue")).To(BeEquivalentTo(f2(94)))      // MediumSlateBlue matches BrightBlue (#94)
+			Expect(f1("RoyalBlue")).To(BeEquivalentTo(f2(94)))            // RoyalBlue matches BrightBlue (#94)
+			Expect(f1("SlateBlue")).To(BeEquivalentTo(f2(94)))            // SlateBlue matches BrightBlue (#94)
+			Expect(f1("SlateGray")).To(BeEquivalentTo(f2(94)))            // SlateGray matches BrightBlue (#94)
+			Expect(f1("SteelBlue")).To(BeEquivalentTo(f2(94)))            // SteelBlue matches BrightBlue (#94)
+			Expect(f1("DeepPink")).To(BeEquivalentTo(f2(95)))             // DeepPink matches BrightMagenta (#95)
+			Expect(f1("Fuchsia")).To(BeEquivalentTo(f2(95)))              // Fuchsia matches BrightMagenta (#95)
+			Expect(f1("HotPink")).To(BeEquivalentTo(f2(95)))              // HotPink matches BrightMagenta (#95)
+			Expect(f1("Magenta")).To(BeEquivalentTo(f2(95)))              // Magenta matches BrightMagenta (#95)
+			Expect(f1("MediumOrchid")).To(BeEquivalentTo(f2(95)))         // MediumOrchid matches BrightMagenta (#95)
+			Expect(f1("Orchid")).To(BeEquivalentTo(f2(95)))               // Orchid matches BrightMagenta (#95)
+			Expect(f1("Plum")).To(BeEquivalentTo(f2(95)))                 // Plum matches BrightMagenta (#95)
+			Expect(f1("Violet")).To(BeEquivalentTo(f2(95)))               // Violet matches BrightMagenta (#95)
+			Expect(f1("Aqua")).To(BeEquivalentTo(f2(96)))                 // Aqua matches BrightCyan (#96)
+			Expect(f1("Aquamarine")).To(BeEquivalentTo(f2(96)))           // Aquamarine matches BrightCyan (#96)
+			Expect(f1("Cyan")).To(BeEquivalentTo(f2(96)))                 // Cyan matches BrightCyan (#96)
+			Expect(f1("LightBlue")).To(BeEquivalentTo(f2(96)))            // LightBlue matches BrightCyan (#96)
+			Expect(f1("MediumTurquoise")).To(BeEquivalentTo(f2(96)))      // MediumTurquoise matches BrightCyan (#96)
+			Expect(f1("PaleTurquoise")).To(BeEquivalentTo(f2(96)))        // PaleTurquoise matches BrightCyan (#96)
+			Expect(f1("PowderBlue")).To(BeEquivalentTo(f2(96)))           // PowderBlue matches BrightCyan (#96)
+			Expect(f1("SkyBlue")).To(BeEquivalentTo(f2(96)))              // SkyBlue matches BrightCyan (#96)
+			Expect(f1("Turquoise")).To(BeEquivalentTo(f2(96)))            // Turquoise matches BrightCyan (#96)
+			Expect(f1("AliceBlue")).To(BeEquivalentTo(f2(97)))            // AliceBlue matches BrightWhite (#97)
+			Expect(f1("AntiqueWhite")).To(BeEquivalentTo(f2(97)))         // AntiqueWhite matches BrightWhite (#97)
+			Expect(f1("Azure")).To(BeEquivalentTo(f2(97)))                // Azure matches BrightWhite (#97)
+			Expect(f1("Beige")).To(BeEquivalentTo(f2(97)))                // Beige matches BrightWhite (#97)
+			Expect(f1("Bisque")).To(BeEquivalentTo(f2(97)))               // Bisque matches BrightWhite (#97)
+			Expect(f1("BlanchedAlmond")).To(BeEquivalentTo(f2(97)))       // BlanchedAlmond matches BrightWhite (#97)
+			Expect(f1("Cornsilk")).To(BeEquivalentTo(f2(97)))             // Cornsilk matches BrightWhite (#97)
+			Expect(f1("FloralWhite")).To(BeEquivalentTo(f2(97)))          // FloralWhite matches BrightWhite (#97)
+			Expect(f1("Gainsboro")).To(BeEquivalentTo(f2(97)))            // Gainsboro matches BrightWhite (#97)
+			Expect(f1("GhostWhite")).To(BeEquivalentTo(f2(97)))           // GhostWhite matches BrightWhite (#97)
+			Expect(f1("Honeydew")).To(BeEquivalentTo(f2(97)))             // Honeydew matches BrightWhite (#97)
+			Expect(f1("Ivory")).To(BeEquivalentTo(f2(97)))                // Ivory matches BrightWhite (#97)
+			Expect(f1("Lavender")).To(BeEquivalentTo(f2(97)))             // Lavender matches BrightWhite (#97)
+			Expect(f1("LavenderBlush")).To(BeEquivalentTo(f2(97)))        // LavenderBlush matches BrightWhite (#97)
+			Expect(f1("LemonChiffon")).To(BeEquivalentTo(f2(97)))         // LemonChiffon matches BrightWhite (#97)
+			Expect(f1("LightCyan")).To(BeEquivalentTo(f2(97)))            // LightCyan matches BrightWhite (#97)
+			Expect(f1("LightGoldenrodYellow")).To(BeEquivalentTo(f2(97))) // LightGoldenrodYellow matches BrightWhite (#97)
+			Expect(f1("LightGray")).To(BeEquivalentTo(f2(97)))            // LightGray matches BrightWhite (#97)
+			Expect(f1("LightYellow")).To(BeEquivalentTo(f2(97)))          // LightYellow matches BrightWhite (#97)
+			Expect(f1("Linen")).To(BeEquivalentTo(f2(97)))                // Linen matches BrightWhite (#97)
+			Expect(f1("MintCream")).To(BeEquivalentTo(f2(97)))            // MintCream matches BrightWhite (#97)
+			Expect(f1("MistyRose")).To(BeEquivalentTo(f2(97)))            // MistyRose matches BrightWhite (#97)
+			Expect(f1("Moccasin")).To(BeEquivalentTo(f2(97)))             // Moccasin matches BrightWhite (#97)
+			Expect(f1("NavajoWhite")).To(BeEquivalentTo(f2(97)))          // NavajoWhite matches BrightWhite (#97)
+			Expect(f1("OldLace")).To(BeEquivalentTo(f2(97)))              // OldLace matches BrightWhite (#97)
+			Expect(f1("PapayaWhip")).To(BeEquivalentTo(f2(97)))           // PapayaWhip matches BrightWhite (#97)
+			Expect(f1("PeachPuff")).To(BeEquivalentTo(f2(97)))            // PeachPuff matches BrightWhite (#97)
+			Expect(f1("Seashell")).To(BeEquivalentTo(f2(97)))             // Seashell matches BrightWhite (#97)
+			Expect(f1("Snow")).To(BeEquivalentTo(f2(97)))                 // Snow matches BrightWhite (#97)
+			Expect(f1("Wheat")).To(BeEquivalentTo(f2(97)))                // Wheat matches BrightWhite (#97)
+			Expect(f1("White")).To(BeEquivalentTo(f2(97)))                // White matches BrightWhite (#97)
+			Expect(f1("WhiteSmoke")).To(BeEquivalentTo(f2(97)))           // WhiteSmoke matches BrightWhite (#97)
+		})
+	})
+})

convenience.go

@@ -119,13 +119,36 @@ func Underline() StyleOption {
 func Foreground(color colorful.Color) StyleOption {
 	return StyleOption{
 		postProcess: func(s *String, flags map[string]struct{}) {
-			r, g, b := color.RGB255()
 			_, skipNewLine := flags["skipNewLine"]
+			_, blendColors := flags["blendColors"]
+
 			for i := range *s {
 				if skipNewLine && (*s)[i].Symbol == '\n' {
 					continue
 				}
 
+				r, g, b := color.RGB255()
+
+				if blendColors && ((*s)[i].Settings>>8&0xFFFFFF) != 0 {
+					currentColor := colorful.Color{
+						R: float64(((*s)[i].Settings >> 8) & 0xFF),
+						G: float64(((*s)[i].Settings >> 16) & 0xFF),
+						B: float64(((*s)[i].Settings >> 24) & 0xFF),
+					}
+
+					targetColor := colorful.Color{
+						R: float64(r),
+						G: float64(g),
+						B: float64(b),
+					}
+
+					// reset RGB values with blended color values
+					r, g, b = targetColor.BlendLab(currentColor, 0.5).RGB255()
+				}
+
+				// reset currently set foreground color
+				(*s)[i].Settings &= 0xFFFFFFFF000000FF
+
 				(*s)[i].Settings |= 1
 				(*s)[i].Settings |= uint64(r) << 8
 				(*s)[i].Settings |= uint64(g) << 16
@@ -152,6 +175,14 @@ func EachLine() StyleOption {
 	}
 }
 
+// Blend enables that applying a color does not completely reset an existing
+// existing color, but rather mixes/blends both colors together.
+func Blend() StyleOption {
+	return StyleOption{
+		flags: []string{"blendColors"},
+	}
+}
+
 // Style is a multi-purpose function to programmatically apply styles and other
 // changes to an input text. The function will panic in the unlikely case of a
 // parse issue.