/
util.go
71 lines (61 loc) · 1.26 KB
/
util.go
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package scrollcanvas
import (
"image"
"image/color"
)
func isBlack(c color.Color) bool {
r, g, b, _ := c.RGBA()
return r == 0 && b == 0 && g == 0
}
func firstNonBlankY(img image.Image) int {
if img == nil {
return 0
}
for y := img.Bounds().Min.Y; y <= img.Bounds().Max.Y; y++ {
for x := img.Bounds().Min.X; x <= img.Bounds().Max.X; x++ {
if !isBlack(img.At(x, y)) {
return y
}
}
}
return img.Bounds().Min.Y
}
func firstNonBlankX(img image.Image) int {
if img == nil {
return 0
}
for x := img.Bounds().Min.X; x <= img.Bounds().Max.X; x++ {
for y := img.Bounds().Min.Y; y <= img.Bounds().Max.Y; y++ {
if !isBlack(img.At(x, y)) {
return x
}
}
}
return img.Bounds().Min.X
}
func lastNonBlankY(img image.Image) int {
if img == nil {
return 0
}
for y := img.Bounds().Max.Y; y >= img.Bounds().Min.Y; y-- {
for x := img.Bounds().Min.X; x <= img.Bounds().Max.X; x++ {
if !isBlack(img.At(x, y)) {
return y
}
}
}
return img.Bounds().Max.Y
}
func lastNonBlankX(img image.Image) int {
if img == nil {
return 0
}
for x := img.Bounds().Max.X; x >= img.Bounds().Min.X; x-- {
for y := img.Bounds().Max.Y; y >= img.Bounds().Min.Y; y-- {
if !isBlack(img.At(x, y)) {
return x
}
}
}
return img.Bounds().Max.X
}