diff options
| -rw-r--r-- | sixel.go | 16 |
1 files changed, 10 insertions, 6 deletions
@@ -13,12 +13,16 @@ import ( "slices" ) +func divRound(n, d uint32) uint32 { + return (n + d/2) / d +} + type sixelRGB struct { r, g, b int8 } func (c sixelRGB) RGBA() (r, g, b, a uint32) { - return uint32(c.r) * 0xffff / 100, uint32(c.g) * 0xffff / 100, uint32(c.b) * 0xffff / 100, 0xffff + return divRound(uint32(c.r)*0xffff, 100), divRound(uint32(c.g)*0xffff, 100), divRound(uint32(c.b)*0xffff, 100), 0xffff } var defaultSixelPalette color.Palette @@ -27,7 +31,7 @@ func init() { defaultSixelPalette = slices.Grow(color.Palette{color.Transparent}, len(palette.WebSafe)) for _, c := range palette.WebSafe { r, g, b, _ := c.RGBA() - defaultSixelPalette = append(defaultSixelPalette, sixelRGB{int8(r * 100 / 0xffff), int8(g * 100 / 0xffff), int8(b * 100 / 0xffff)}) + defaultSixelPalette = append(defaultSixelPalette, sixelRGB{int8(divRound(r*100, 0xffff)), int8(divRound(g*100, 0xffff)), int8(divRound(b*100, 0xffff))}) } } @@ -40,7 +44,7 @@ func sixelizePalette(p color.Palette) color.Palette { includeTransparent = true continue } - result = append(result, sixelRGB{r: int8(r * 100 / 0xffff), g: int8(g * 100 / 0xffff), b: int8(b * 100 / 0xffff)}) + result = append(result, sixelRGB{r: int8(divRound(r*100, 0xffff)), g: int8(divRound(g*100, 0xffff)), b: int8(divRound(b*100, 0xffff))}) } if includeTransparent { result = append(color.Palette{color.Transparent}, result...) @@ -182,14 +186,14 @@ func PrintBlock(w io.Writer, img image.Image) error { } } else { r, g, b, _ := img.At(x, y+1).RGBA() - if _, err := fmt.Fprintf(bw, "\033[38;2;%d;%d;%dm\033[49m▄", r>>8, g>>8, b>>8); err != nil { + if _, err := fmt.Fprintf(bw, "\033[38;2;%d;%d;%dm\033[49m▄", divRound(r, 1<<8), divRound(g, 1<<8), divRound(b, 1<<8)); err != nil { return err } } } else { if y+1 < img.Bounds().Max.Y && !isFullyTransparent(img.At(x, y+1)) { r, g, b, _ := img.At(x, y+1).RGBA() - if _, err := fmt.Fprintf(bw, "\033[48;2;%d;%d;%dm", r>>8, g>>8, b>>8); err != nil { + if _, err := fmt.Fprintf(bw, "\033[48;2;%d;%d;%dm", divRound(r, 1<<8), divRound(g, 1<<8), divRound(b, 1<<8)); err != nil { return err } } else { @@ -198,7 +202,7 @@ func PrintBlock(w io.Writer, img image.Image) error { } } r, g, b, _ := hi.RGBA() - if _, err := fmt.Fprintf(bw, "\033[38;2;%d;%d;%dm▀", r>>8, g>>8, b>>8); err != nil { + if _, err := fmt.Fprintf(bw, "\033[38;2;%d;%d;%dm▀", divRound(r, 1<<8), divRound(g, 1<<8), divRound(b, 1<<8)); err != nil { return err } } |