init commit

internal/ui/waveform/render.go

@@ -0,0 +1,77 @@
+package waveform
+
+// Block characters for waveform rendering (bottom to top)
+var blocks = []rune{' ', '▁', '▂', '▃', '▄', '▅', '▆', '▇', '█'}
+
+// RenderWaveform converts normalized samples (0-1) to block characters
+func RenderWaveform(samples []float64, width int) string {
+	if len(samples) == 0 {
+		return ""
+	}
+
+	result := make([]rune, width)
+
+	for i := 0; i < width; i++ {
+		// Map position to sample index
+		sampleIdx := i * len(samples) / width
+		if sampleIdx >= len(samples) {
+			sampleIdx = len(samples) - 1
+		}
+
+		// Get sample value and map to block character
+		value := samples[sampleIdx]
+		if value < 0 {
+			value = 0
+		}
+		if value > 1 {
+			value = 1
+		}
+
+		blockIdx := int(value * float64(len(blocks)-1))
+		result[i] = blocks[blockIdx]
+	}
+
+	return string(result)
+}
+
+// RenderWaveformWithNeedle renders the waveform with a position indicator
+func RenderWaveformWithNeedle(samples []float64, width int, position float64) (string, int) {
+	waveform := RenderWaveform(samples, width)
+
+	// Calculate needle position
+	needlePos := int(position * float64(width))
+	if needlePos < 0 {
+		needlePos = 0
+	}
+	if needlePos >= width {
+		needlePos = width - 1
+	}
+
+	return waveform, needlePos
+}
+
+// RenderWithColors returns the waveform with the needle position marked
+// Returns: left part, needle char, right part
+func RenderWithColors(samples []float64, width int, position float64) (string, string, string) {
+	waveform := []rune(RenderWaveform(samples, width))
+	if len(waveform) == 0 {
+		return "", "|", ""
+	}
+
+	needlePos := int(position * float64(len(waveform)))
+	if needlePos < 0 {
+		needlePos = 0
+	}
+	if needlePos >= len(waveform) {
+		needlePos = len(waveform) - 1
+	}
+
+	left := string(waveform[:needlePos])
+	needle := "|"
+	right := ""
+	if needlePos+1 < len(waveform) {
+		right = string(waveform[needlePos+1:])
+	}
+
+	return left, needle, right
+}