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menu: faster background drawing using FastHLines #6

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menu: faster background drawing using FastHLines #6

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81 changes: 75 additions & 6 deletions menu.go
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,75 @@ import (
"tinygo.org/x/tinyfont/proggy"
)

// FilledTriangle draws a filled triangle given three points
// Code from tinydraw, but faster and may not work on all displays
func FilledTriangle(x0 int16, y0 int16, x1 int16, y1 int16, x2 int16, y2 int16, color color.RGBA) {
if y0 > y1 {
x0, y0, x1, y1 = x1, y1, x0, y0
}
if y1 > y2 {
x1, y1, x2, y2 = x2, y2, x1, y1
}
if y0 > y1 {
x0, y0, x1, y1 = x1, y1, x0, y0
}

if y0 == y2 { // y0 = y1 = y2 : it's a line
a := x0
b := x0
if x1 < a {
a = x1
} else if x1 > b {
b = x1
}
if x2 < a {
a = x2
} else if x2 > b {
b = x2
}
// Line(display, a, y0, b, y0, color)
display.DrawFastHLine(a, b, y0, color)
return
}

dx01 := x1 - x0
dy01 := y1 - y0
dx02 := x2 - x0
dy02 := y2 - y0
dx12 := x2 - x1
dy12 := y2 - y1

sa := int16(0)
sb := int16(0)
a := int16(0)
b := int16(0)

last := y1 - 1
if y1 == y2 {
last = y1
}

y := y0
for ; y <= last; y++ {
a = x0 + sa/dy01
b = x0 + sb/dy02
sa += dx01
sb += dx02
display.DrawFastHLine(a, b, y, color)
}

sa = dx12 * (y - y1)
sb = dx02 * (y - y0)

for ; y <= y2; y++ {
a = x1 + sa/dy12
b = x0 + sb/dy02
sa += dx12
sb += dx02
display.DrawFastHLine(a, b, y, color)
}
}

func menu() int16 {
display.FillScreen(color.RGBA{0, 0, 0, 255})
options := []string{
Expand All @@ -23,12 +92,12 @@ func menu() int16 {

bgColor := color.RGBA{0, 40, 70, 255}
display.FillScreen(bgColor)
tinydraw.FilledTriangle(&display, 0, 128, 0, 45, 45, 0, color.RGBA{255, 255, 255, 255})
tinydraw.FilledTriangle(&display, 45, 0, 0, 128, 145, 0, color.RGBA{255, 255, 255, 255})
tinydraw.FilledTriangle(&display, 0, 128, 15, 128, 145, 0, color.RGBA{255, 255, 255, 255})
for i := int16(0); i < 8; i++ {
tinydraw.Line(&display, 0, 110+i, 110+i, 0, bgColor)
}
FilledTriangle(0, 128, 0, 45, 45, 0, color.RGBA{255, 255, 255, 255})
FilledTriangle(45, 0, 0, 128, 145, 0, color.RGBA{255, 255, 255, 255})
FilledTriangle(0, 128, 15, 128, 145, 0, color.RGBA{255, 255, 255, 255})

FilledTriangle(0, 110, 110, 0, 117, 0, bgColor)
FilledTriangle(0, 110, 0, 117, 117, 0, bgColor)

selected := int16(0)
numOpts := int16(len(options))
Expand Down