Add monochrome palette

References #96.

MANUAL.md

@@ -56,6 +56,9 @@ On OS X use the Command key instead of Ctrl.
 `s`, `S`
 :   Change the DFT window size.
 
+`p`, `P`
+:   Change the palette.
+
 # FILES
 
 *~/.config/spek/preferences*

src/spek-palette.cc

@@ -1,8 +1,10 @@
+#include <assert.h>
+
 #include "spek-palette.h"
 
 // Modified version of Dan Bruton's algorithm:
 // http://www.physics.sfasu.edu/astro/color/spectra.html
-uint32_t spek_palette_spectrum(double level)
+static uint32_t spectrum(double level)
 {
     level *= 0.6625;
     double r = 0.0, g = 0.0, b = 0.0;
@@ -41,3 +43,21 @@ uint32_t spek_palette_spectrum(double level)
     uint32_t bb = (uint32_t) (b * cf + 0.5);
     return (rr << 16) + (gg << 8) + bb;
 }
+
+static uint32_t mono(double level)
+{
+    uint32_t v = (uint32_t) (level * 255.0 + 0.5);
+    return (v << 16) + (v << 8) + v;
+}
+
+uint32_t spek_palette(enum palette palette, double level) {
+    switch (palette) {
+    case PALETTE_SPECTRUM:
+        return spectrum(level);
+    case PALETTE_MONO:
+        return mono(level);
+    default:
+        assert(false);
+        return 0;
+    }
+}

src/spek-palette.h

@@ -2,4 +2,11 @@
 
 #include <stdint.h>
 
-uint32_t spek_palette_spectrum(double level);
+enum palette {
+    PALETTE_SPECTRUM,
+    PALETTE_MONO,
+    PALETTE_COUNT,
+    PALETTE_DEFAULT = PALETTE_SPECTRUM,
+};
+
+uint32_t spek_palette(enum palette palette, double level);

src/spek-spectrogram.cc

@@ -5,7 +5,6 @@
 #include "spek-audio.h"
 #include "spek-events.h"
 #include "spek-fft.h"
-#include "spek-palette.h"
 #include "spek-pipeline.h"
 #include "spek-platform.h"
 #include "spek-ruler.h"
@@ -51,7 +50,8 @@ SpekSpectrogram::SpekSpectrogram(wxFrame *parent) :
     pipeline(NULL),
     duration(0.0),
     sample_rate(0),
-    palette(),
+    palette(PALETTE_DEFAULT),
+    palette_image(),
     image(1, 1),
     prev_width(-1),
     fft_bits(FFT_BITS),
@@ -108,6 +108,12 @@ void SpekSpectrogram::on_char(wxKeyEvent& evt)
     } else if (N && evt.GetKeyCode() == 's') {
         this->fft_bits = spek_max(this->fft_bits - 1, MIN_FFT_BITS);
         this->create_palette();
+    } else if (S && evt.GetKeyCode() == 'P') {
+        this->palette = (enum palette) ((this->palette + 1) % PALETTE_COUNT);
+        this->create_palette();
+    } else if (N && evt.GetKeyCode() == 'p') {
+        this->palette = (enum palette) ((this->palette - 1 + PALETTE_COUNT) % PALETTE_COUNT);
+        this->create_palette();
     } else {
         evt.Skip();
         return;
@@ -150,7 +156,7 @@ void SpekSpectrogram::on_have_sample(SpekHaveSampleEvent& event)
     for (int y = 0; y < bands; y++) {
         double value = fmin(this->urange, fmax(this->lrange, values[y]));
         double level = (value - this->lrange) / range;
-        uint32_t color = spek_palette_spectrum(level);
+        uint32_t color = spek_palette(this->palette, level);
         this->image.SetRGB(
             sample,
             bands - y - 1,
@@ -301,7 +307,7 @@ void SpekSpectrogram::render(wxDC& dc)
 
     // The palette.
     if (h - TPAD - BPAD > 0) {
-        wxBitmap bmp(this->palette.Scale(RULER, h - TPAD - BPAD + 1));
+        wxBitmap bmp(this->palette_image.Scale(RULER, h - TPAD - BPAD + 1));
         dc.DrawBitmap(bmp, w - RPAD + GAP, TPAD);
 
         // Prepare to draw the ruler.
@@ -379,10 +385,10 @@ void SpekSpectrogram::stop()
 
 void SpekSpectrogram::create_palette()
 {
-    this->palette.Create(RULER, bits_to_bands(this->fft_bits));
+    this->palette_image.Create(RULER, bits_to_bands(this->fft_bits));
     for (int y = 0; y < bits_to_bands(this->fft_bits); y++) {
-        uint32_t color = spek_palette_spectrum(y / (double)bits_to_bands(this->fft_bits));
+        uint32_t color = spek_palette(this->palette, y / (double)bits_to_bands(this->fft_bits));
-        this->palette.SetRGB(
+        this->palette_image.SetRGB(
             wxRect(0, bits_to_bands(this->fft_bits) - y - 1, RULER, 1),
             color >> 16,
             (color >> 8) & 0xFF,

src/spek-spectrogram.h

@@ -4,6 +4,8 @@
 
 #include <wx/wx.h>
 
+#include "spek-palette.h"
+
 class Audio;
 class FFT;
 class SpekHaveSampleEvent;
@@ -36,7 +38,8 @@ private:
     wxString desc;
     double duration;
     int sample_rate;
-    wxImage palette;
+    enum palette palette;
+    wxImage palette_image;
     wxImage image;
     int prev_width;
     int fft_bits;