text: 256 and true color support

jedib0t · Aug 31, 2023 · a6ce26d · a6ce26d
1 parent 05c0986
commit a6ce26d
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Showing 5 changed files with 171 additions and 0 deletions.
diff --git a/text/colors_256.go b/text/colors_256.go
@@ -0,0 +1,49 @@
+package text
+
+import (
+	"fmt"
+)
+
+const (
+	escCodeColor256Background = "48;5;"
+	escCodeColor256Foreground = "38;5;"
+)
+
+// Colors256 contains 8-bit (256) colors for foreground and background.
+type Colors256 struct {
+	Background uint8 `json:"background"`
+	Foreground uint8 `json:"foreground"`
+}
+
+var (
+	mapColors256EscapeSeq = map[uint]string{}
+)
+
+// EscapeSeq returns the ANSI escape sequence for the color.
+func (c Colors256) EscapeSeq() string {
+	mapKey := (uint(c.Background) * 1000) + uint(c.Foreground)
+	if _, ok := mapColors256EscapeSeq[mapKey]; !ok {
+		mapColors256EscapeSeq[mapKey] = fmt.Sprintf("%s%s%d;%s%d;%s",
+			EscapeStart,
+			escCodeColor256Background, c.Background,
+			escCodeColor256Foreground, c.Foreground,
+			EscapeStop,
+		)
+	}
+	return mapColors256EscapeSeq[mapKey]
+}
+
+// HTMLProperty returns the "style" attribute for the colors with for.
+func (c Colors256) HTMLProperty() string {
+	return "" // TODO
+}
+
+// Sprint colorizes and prints the given string(s).
+func (c Colors256) Sprint(a ...interface{}) string {
+	return colorize(fmt.Sprint(a...), c.EscapeSeq())
+}
+
+// Sprintf formats and colorizes and prints the given string(s).
+func (c Colors256) Sprintf(format string, a ...interface{}) string {
+	return colorize(fmt.Sprintf(format, a...), c.EscapeSeq())
+}
diff --git a/text/colors_256.png b/text/colors_256.png
diff --git a/text/colors_true.go b/text/colors_true.go
@@ -0,0 +1,53 @@
+package text
+
+import (
+	"fmt"
+	"strings"
+)
+
+const (
+	escCodeColorRGBForeground = "38;2;"
+	escCodeColorRGBBackground = "48;2;"
+)
+
+// ColorsTrue represents True-color values for foreground and background.
+type ColorsTrue struct {
+	Foreground RGB `json:"foreground"`
+	Background RGB `json:"background"`
+
+	escapeSeq string
+}
+
+// EscapeSeq returns the ANSI escape sequence for the color.
+func (c ColorsTrue) EscapeSeq() string {
+	if c.escapeSeq == "" {
+		c.escapeSeq = fmt.Sprintf("%s%s%d;%d;%d;%s%d;%d;%d;%s",
+			EscapeStart,
+			escCodeColorRGBForeground, c.Foreground.R, c.Foreground.G, c.Foreground.B,
+			escCodeColorRGBBackground, c.Background.R, c.Background.G, c.Background.B,
+			EscapeStop,
+		)
+	}
+	return c.escapeSeq
+}
+
+// HTMLProperty returns the "style" attribute for the colors with for.
+func (c ColorsTrue) HTMLProperty() string {
+	sb := strings.Builder{}
+	sb.WriteString("style=\"")
+	sb.WriteString(fmt.Sprintf("color: #%s;", c.Foreground.HexValue()))
+	sb.WriteString(fmt.Sprintf("background-color: #%s;", c.Background.HexValue()))
+	sb.WriteString("\"")
+	return sb.String()
+}
+
+// Sprint colorizes and
+// Sprint colorizes and prints the given string(s).
+func (c ColorsTrue) Sprint(a ...interface{}) string {
+	return colorize(fmt.Sprint(a...), c.EscapeSeq())
+}
+
+// Sprintf formats and colorizes and prints the given string(s).
+func (c ColorsTrue) Sprintf(format string, a ...interface{}) string {
+	return colorize(fmt.Sprintf(format, a...), c.EscapeSeq())
+}
diff --git a/text/rgb.go b/text/rgb.go
@@ -0,0 +1,22 @@
+package text
+
+import "fmt"
+
+// RGB contains the Red/Green/Blue values that make up a True Color.
+type RGB struct {
+	R uint8 `json:"r"`
+	G uint8 `json:"g"`
+	B uint8 `json:"b"`
+}
+
+func (rgb RGB) HexValue() string {
+	return fmt.Sprintf("#%02x%02x%02x", rgb.R, rgb.G, rgb.B)
+}
+
+func RGBFrom8BitColor(c uint8) RGB {
+	return RGB{
+		R: (((c >> 5) & 0x07) * 255) / 7,
+		G: (((c >> 2) & 0x07) * 255) / 7,
+		B: ((c & 0x03) * 255) / 3,
+	}
+}
diff --git a/text/rgb_test.go b/text/rgb_test.go
@@ -0,0 +1,47 @@
+package text
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRGB_HexValue(t *testing.T) {
+	assert.Equal(t, "#000000", RGB{0, 0, 0}.HexValue())
+	assert.Equal(t, "#ff0000", RGB{255, 0, 0}.HexValue())
+	assert.Equal(t, "#00ff00", RGB{0, 255, 0}.HexValue())
+	assert.Equal(t, "#0000ff", RGB{0, 0, 255}.HexValue())
+	assert.Equal(t, "#ffffff", RGB{255, 255, 255}.HexValue())
+	assert.Equal(t, "#7f7f7f", RGB{127, 127, 127}.HexValue())
+}
+
+func TestRGBFrom8BitColor(t *testing.T) {
+	sb := strings.Builder{}
+	sb.WriteString("<html><table>\n")
+	for idx := uint8(0); idx <= uint8(255); idx++ {
+		if idx == 0 || (idx > 15 && idx < 232 && ((idx-16)%36) == 0) || idx == 232 {
+			sb.WriteString("<tr>\n")
+		}
+		if idx == 8 || idx == 244 {
+			sb.WriteString("<td>&nbsp;</td>")
+		}
+		rgb := RGBFrom8BitColor(idx)
+		sb.WriteString(
+			fmt.Sprintf(
+				"<td style=\"background-color: %s\">%03d</td>\n",
+				rgb.HexValue(), idx,
+			),
+		)
+		if idx == 15 || (idx > 15 && idx < 232 && ((idx-16)%36) == 35) || idx == 255 {
+			sb.WriteString("</tr>\n")
+		}
+		if idx == 255 {
+			break
+		}
+	}
+	sb.WriteString("</table></html>\n")
+
+	fmt.Println(sb.String())
+}