First Commit

libui-ng/old/_doc/export/ttfixedtest.go

@@ -0,0 +1,58 @@
+// 2 november 2017
+package main
+
+import (
+	"fmt"
+)
+
+type fixed1616 uint32
+type fixed214 uint16
+
+func fixed1616To214(f fixed1616) fixed214 {
+	f += 0x00000002
+	g := int32(f) >> 2
+	return fixed214(uint32(g) & 0xFFFF)
+}
+
+func (f fixed1616) In214Range() bool {
+	base := int16((f >> 16) & 0xFFFF)
+	return base >= -2 && base < 2
+}
+
+func (f fixed1616) String() string {
+	base := int16((f >> 16) & 0xFFFF)
+	frac := float64(f & 0xFFFF) / 65536
+	res := float64(base) + frac
+	return fmt.Sprintf("%f 0x%08X", res, uint32(f))
+}
+
+func (f fixed214) String() string {
+	base := []int16{
+		0,
+		1,
+		-2,
+		-1,
+	}[(f & 0xC000) >> 14]
+	frac := float64(f & 0x3FFF) / 16384
+	res := float64(base) + frac
+	return fmt.Sprintf("%f 0x%04X", res, uint16(f))
+}
+
+func main() {
+	fmt.Println(fixed214(0x7fff))
+	fmt.Println(fixed214(0x8000))
+	fmt.Println(fixed214(0x4000))
+	fmt.Println(fixed214(0xc000))
+	fmt.Println(fixed214(0x7000))
+	fmt.Println(fixed214(0x0000))
+	fmt.Println(fixed214(0x0001))
+	fmt.Println(fixed214(0xffff))
+
+	fmt.Println()
+
+	for i := uint64(0x00000000); i <= 0xFFFFFFFF; i++ {
+		j := fixed1616(i)
+		if !j.In214Range() { continue }
+		fmt.Println(j, "->", fixed1616To214(j))
+	}
+}