cmap-metal.ipynb

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 1,
   "id": "bcdb2d98",
   "metadata": {},
   "outputs": [],
   "source": [
    "import matplotlib"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "id": "6f7fe68f",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['magma',\n",
       " 'inferno',\n",
       " 'plasma',\n",
       " 'viridis',\n",
       " 'cividis',\n",
       " 'twilight',\n",
       " 'twilight_shifted',\n",
       " 'turbo',\n",
       " 'berlin',\n",
       " 'managua',\n",
       " 'vanimo',\n",
       " 'Blues',\n",
       " 'BrBG',\n",
       " 'BuGn',\n",
       " 'BuPu',\n",
       " 'CMRmap',\n",
       " 'GnBu',\n",
       " 'Greens',\n",
       " 'Greys',\n",
       " 'OrRd',\n",
       " 'Oranges',\n",
       " 'PRGn',\n",
       " 'PiYG',\n",
       " 'PuBu',\n",
       " 'PuBuGn',\n",
       " 'PuOr',\n",
       " 'PuRd',\n",
       " 'Purples',\n",
       " 'RdBu',\n",
       " 'RdGy',\n",
       " 'RdPu',\n",
       " 'RdYlBu',\n",
       " 'RdYlGn',\n",
       " 'Reds',\n",
       " 'Spectral',\n",
       " 'Wistia',\n",
       " 'YlGn',\n",
       " 'YlGnBu',\n",
       " 'YlOrBr',\n",
       " 'YlOrRd',\n",
       " 'afmhot',\n",
       " 'autumn',\n",
       " 'binary',\n",
       " 'bone',\n",
       " 'brg',\n",
       " 'bwr',\n",
       " 'cool',\n",
       " 'coolwarm',\n",
       " 'copper',\n",
       " 'cubehelix',\n",
       " 'flag',\n",
       " 'gist_earth',\n",
       " 'gist_gray',\n",
       " 'gist_heat',\n",
       " 'gist_ncar',\n",
       " 'gist_rainbow',\n",
       " 'gist_stern',\n",
       " 'gist_yarg',\n",
       " 'gnuplot',\n",
       " 'gnuplot2',\n",
       " 'gray',\n",
       " 'hot',\n",
       " 'hsv',\n",
       " 'jet',\n",
       " 'nipy_spectral',\n",
       " 'ocean',\n",
       " 'pink',\n",
       " 'prism',\n",
       " 'rainbow',\n",
       " 'seismic',\n",
       " 'spring',\n",
       " 'summer',\n",
       " 'terrain',\n",
       " 'winter',\n",
       " 'Accent',\n",
       " 'Dark2',\n",
       " 'Paired',\n",
       " 'Pastel1',\n",
       " 'Pastel2',\n",
       " 'Set1',\n",
       " 'Set2',\n",
       " 'Set3',\n",
       " 'tab10',\n",
       " 'tab20',\n",
       " 'tab20b',\n",
       " 'tab20c',\n",
       " 'grey',\n",
       " 'gist_grey',\n",
       " 'gist_yerg',\n",
       " 'Grays',\n",
       " 'magma_r',\n",
       " 'inferno_r',\n",
       " 'plasma_r',\n",
       " 'viridis_r',\n",
       " 'cividis_r',\n",
       " 'twilight_r',\n",
       " 'twilight_shifted_r',\n",
       " 'turbo_r',\n",
       " 'berlin_r',\n",
       " 'managua_r',\n",
       " 'vanimo_r',\n",
       " 'Blues_r',\n",
       " 'BrBG_r',\n",
       " 'BuGn_r',\n",
       " 'BuPu_r',\n",
       " 'CMRmap_r',\n",
       " 'GnBu_r',\n",
       " 'Greens_r',\n",
       " 'Greys_r',\n",
       " 'OrRd_r',\n",
       " 'Oranges_r',\n",
       " 'PRGn_r',\n",
       " 'PiYG_r',\n",
       " 'PuBu_r',\n",
       " 'PuBuGn_r',\n",
       " 'PuOr_r',\n",
       " 'PuRd_r',\n",
       " 'Purples_r',\n",
       " 'RdBu_r',\n",
       " 'RdGy_r',\n",
       " 'RdPu_r',\n",
       " 'RdYlBu_r',\n",
       " 'RdYlGn_r',\n",
       " 'Reds_r',\n",
       " 'Spectral_r',\n",
       " 'Wistia_r',\n",
       " 'YlGn_r',\n",
       " 'YlGnBu_r',\n",
       " 'YlOrBr_r',\n",
       " 'YlOrRd_r',\n",
       " 'afmhot_r',\n",
       " 'autumn_r',\n",
       " 'binary_r',\n",
       " 'bone_r',\n",
       " 'brg_r',\n",
       " 'bwr_r',\n",
       " 'cool_r',\n",
       " 'coolwarm_r',\n",
       " 'copper_r',\n",
       " 'cubehelix_r',\n",
       " 'flag_r',\n",
       " 'gist_earth_r',\n",
       " 'gist_gray_r',\n",
       " 'gist_heat_r',\n",
       " 'gist_ncar_r',\n",
       " 'gist_rainbow_r',\n",
       " 'gist_stern_r',\n",
       " 'gist_yarg_r',\n",
       " 'gnuplot_r',\n",
       " 'gnuplot2_r',\n",
       " 'gray_r',\n",
       " 'hot_r',\n",
       " 'hsv_r',\n",
       " 'jet_r',\n",
       " 'nipy_spectral_r',\n",
       " 'ocean_r',\n",
       " 'pink_r',\n",
       " 'prism_r',\n",
       " 'rainbow_r',\n",
       " 'seismic_r',\n",
       " 'spring_r',\n",
       " 'summer_r',\n",
       " 'terrain_r',\n",
       " 'winter_r',\n",
       " 'Accent_r',\n",
       " 'Dark2_r',\n",
       " 'Paired_r',\n",
       " 'Pastel1_r',\n",
       " 'Pastel2_r',\n",
       " 'Set1_r',\n",
       " 'Set2_r',\n",
       " 'Set3_r',\n",
       " 'tab10_r',\n",
       " 'tab20_r',\n",
       " 'tab20b_r',\n",
       " 'tab20c_r',\n",
       " 'grey_r',\n",
       " 'gist_grey_r',\n",
       " 'gist_yerg_r',\n",
       " 'Grays_r']"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "list(matplotlib.colormaps)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "id": "bee80bb9",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "<class 'matplotlib.colors.ListedColormap'>\n",
      "256\n"
     ]
    },
    {
     "data": {
      "image/png": "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",
      "text/html": [
       "<div style=\"vertical-align: middle;\"><strong>viridis</strong> </div><div class=\"cmap\"><img alt=\"viridis colormap\" title=\"viridis\" style=\"border: 1px solid #555;\" src=\"data:image/png;base64,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\"></div><div style=\"vertical-align: middle; max-width: 514px; display: flex; justify-content: space-between;\"><div style=\"float: left;\"><div title=\"#440154ff\" style=\"display: inline-block; width: 1em; height: 1em; margin: 0; vertical-align: middle; border: 1px solid #555; background-color: #440154ff;\"></div> under</div><div style=\"margin: 0 auto; display: inline-block;\">bad <div title=\"#00000000\" style=\"display: inline-block; width: 1em; height: 1em; margin: 0; vertical-align: middle; border: 1px solid #555; background-color: #00000000;\"></div></div><div style=\"float: right;\">over <div title=\"#fde725ff\" style=\"display: inline-block; width: 1em; height: 1em; margin: 0; vertical-align: middle; border: 1px solid #555; background-color: #fde725ff;\"></div></div></div>"
      ],
      "text/plain": [
       "<matplotlib.colors.ListedColormap at 0x110e37680>"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "cm = matplotlib.colormaps[\"viridis\"]\n",
    "print(type(cm))\n",
    "print(len(cm.colors))\n",
    "cm"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "id": "b9e7cc13",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "#ifndef CMAP_H\n",
      "#define CMAP_H\n",
      "#ifdef __METAL_VERSION__\n",
      "#define CMAP_CONST constant\n",
      "#else\n",
      "#define CMAP_CONST const\n",
      "#define saturate(x) ((x) < 0 ? 0 : (x) > 1 ? 1 : (x))\n",
      "#define mix(x, y, a) ((x) + ((y) - (x)) * (a))\n",
      "#endif\n",
      "\n",
      "float3 _cmap_piecewise_linear(float x, CMAP_CONST float3* table, int n) {\n",
      "    float scaled = saturate(x) * (n - 1);\n",
      "    int i = (int)scaled;\n",
      "    float t = scaled - i;\n",
      "    return mix(table[i], table[i + 1], t);\n",
      "}\n",
      "\n",
      "CMAP_CONST float3 _table_viridis[] = {\n",
      "    float3(0.267004, 0.004874, 0.329415),\n",
      "    float3(0.277018, 0.050344, 0.375715),\n",
      "    float3(0.282327, 0.094955, 0.417331),\n",
      "    float3(0.282884, 0.13592, 0.453427),\n",
      "    float3(0.278012, 0.180367, 0.486697),\n",
      "    float3(0.269308, 0.218818, 0.509577),\n",
      "    float3(0.257322, 0.25613, 0.526563),\n",
      "    float3(0.243113, 0.292092, 0.538516),\n",
      "    float3(0.225863, 0.330805, 0.547314),\n",
      "    float3(0.210503, 0.363727, 0.552206),\n",
      "    float3(0.19586, 0.395433, 0.555276),\n",
      "    float3(0.182256, 0.426184, 0.55712),\n",
      "    float3(0.168126, 0.459988, 0.558082),\n",
      "    float3(0.15627, 0.489624, 0.557936),\n",
      "    float3(0.144759, 0.519093, 0.556572),\n",
      "    float3(0.133743, 0.548535, 0.553541),\n",
      "    float3(0.123463, 0.581687, 0.547445),\n",
      "    float3(0.119423, 0.611141, 0.538982),\n",
      "    float3(0.12478, 0.640461, 0.527068),\n",
      "    float3(0.143303, 0.669459, 0.511215),\n",
      "    float3(0.180653, 0.701402, 0.488189),\n",
      "    float3(0.226397, 0.728888, 0.462789),\n",
      "    float3(0.281477, 0.755203, 0.432552),\n",
      "    float3(0.344074, 0.780029, 0.397381),\n",
      "    float3(0.421908, 0.805774, 0.35191),\n",
      "    float3(0.496615, 0.826376, 0.306377),\n",
      "    float3(0.575563, 0.844566, 0.256415),\n",
      "    float3(0.657642, 0.860219, 0.203082),\n",
      "    float3(0.751884, 0.874951, 0.143228),\n",
      "    float3(0.83527, 0.886029, 0.102646),\n",
      "    float3(0.916242, 0.896091, 0.100717),\n",
      "    float3(0.993248, 0.906157, 0.143936),\n",
      "};\n",
      "\n",
      "float3 viridis(float x) {\n",
      "    return _cmap_piecewise_linear(x, _table_viridis, sizeof(_table_viridis) / sizeof(float3));\n",
      "}\n",
      "\n",
      "#endif\n"
     ]
    }
   ],
   "source": [
    "print(\"\"\"#ifndef CMAP_H\n",
    "#define CMAP_H\n",
    "#ifdef __METAL_VERSION__\n",
    "#define CMAP_CONST constant\n",
    "#else\n",
    "#define CMAP_CONST const\n",
    "#define saturate(x) ((x) < 0 ? 0 : (x) > 1 ? 1 : (x))\n",
    "#define mix(x, y, a) ((x) + ((y) - (x)) * (a))\n",
    "#endif\n",
    "\"\"\")\n",
    "\n",
    "print(f\"float3 _cmap_piecewise_linear(float x, CMAP_CONST float3* table, int n) {{\")\n",
    "print(f\"    float scaled = saturate(x) * (n - 1);\")\n",
    "print(f\"    int i = (int)scaled;\")\n",
    "print(f\"    float t = scaled - i;\")\n",
    "print(f\"    return mix(table[i], table[i + 1], t);\")\n",
    "print(\"}\")\n",
    "print()\n",
    "\n",
    "def format_cmap(cm):\n",
    "    table_name = f\"_table_{cm.name}\"\n",
    "    print(f\"CMAP_CONST float3 {table_name}[] = {{\")\n",
    "    for color in cm.colors:\n",
    "        print(f\"    float3({color[0]}, {color[1]}, {color[2]}),\")\n",
    "    print(\"};\")\n",
    "    print()\n",
    "\n",
    "    print(f\"float3 {cm.name}(float x) {{\")\n",
    "    print(f\"    return _cmap_piecewise_linear(x, {table_name}, sizeof({table_name}) / sizeof(float3));\")\n",
    "    print(\"}\")\n",
    "    print()\n",
    "\n",
    "format_cmap(matplotlib.colormaps[\"viridis\"].resampled(32))\n",
    "\n",
    "print(\"#endif\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "b52d2d97",
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
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