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Use the visible spectrum

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This commit is contained in:
Alexander Kojevnikov 2010-05-06 19:55:21 +10:00
parent 22c477b4a2
commit fe96c4d1e3
1 changed files with 53 additions and 4 deletions
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57
src/spek-spectrogram.vala
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@ -6,6 +6,8 @@ namespace Spek {
private Source source;
private struct Color { uchar r; uchar g; uchar b; }
public Spectrogram () {
}
@ -22,12 +24,59 @@ namespace Spek {
for (int y = 0; y < values.length; y++) {
var i = (values.length - y - 1) * rowstride + x * 3;
var level = float.min (1f, Math.log10f (101f + values[y]) / 2f);
var value = (uchar) (level * 255f);
pixels[i] = value;
pixels[i + 1] = value;
pixels[i + 2] = value;
var color = get_color (level);
if (sample < 20) {
// TODO: allocate additional space for this.
color = get_color (((float) y) / values.length);
}
pixels[i] = color.r;
pixels[i + 1] = color.g;
pixels[i + 2] = color.b;
}
queue_draw_area (allocation.x + sample, allocation.y, 1, allocation.height);
}
// Modified version of Dan Bruton's algorithm:
// http://www.physics.sfasu.edu/astro/color/spectra.html
private Color get_color (float level) {
float r = 0.0f, g = 0.0f, b = 0.0f;
if (level >= 0f && level < 0.15f) {
r = (0.15f - level) / (0.15f + 0.075f);
g = 0.0f;
b = 1.0f;
} else if (level >= 0.15f && level < 0.275f) {
r = 0.0f;
g = (level - 0.15f) / (0.275f - 0.15f);
b = 1.0f;
} else if (level >= 0.275f && level < 0.325f) {
r = 0.0f;
g = 1.0f;
b = (0.325f - level) / (0.325f - 0.275f);
} else if (level >= 0.325f && level < 0.5f) {
r = (level - 0.325f) / (0.5f - 0.325f);
g = 1.0f;
b = 0.0f;
} else if (level >= 0.5f && level < 0.6625f) {
r = 1.0f;
g = (0.6625f - level) / (0.6625f - 0.5f);
b = 0.0f;
} else if (level >= 0.6625 && level <= 1.0f) {
r = 1.0f;
g = 0.0f;
b = 0.0f;
}
// Intensity correction.
float cf = 0.0f;
if (level >= 0 && level < 0.1f) {
cf = 0.3f + 0.7f * (level + 0.075f) / (0.1f + 0.075f);
} else if (level >= 0.1f && level <= 0.8f) {
cf = 1.0f;
} else if (level > 0.8f && level <= 1.0f) {
cf = 0.3f + 0.7f * (1.0f - level) / (1.0f - 0.8f);
}
cf *= 255f;
return { (uchar) (r * cf + 0.5f), (uchar) (g * cf + 0.5f), (uchar) (b * cf + 0.5f) };
}
}
}