Add ktx

2026-06-14 19:09:18 +01:00
parent 14bd1a9271
commit 13fa90a0e9
3958 changed files with 999286 additions and 4 deletions
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+/*
+LodePNG Examples
+
+Copyright (c) 2005-2012 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+*/
+
+/*
+This example saves the PNG with the best compression LodePNG can do, and with
+unnecessary chunks removed. It tries out several combinations of settings and
+keeps the smallest one.
+
+NOTE: This is not as good as a true PNG optimizer like optipng or pngcrush.
+*/
+
+//g++ lodepng.cpp example_optimize_png.cpp -ansi -pedantic -Wall -Wextra -O3
+
+#include "lodepng.h"
+
+#include <iostream>
+
+int main(int argc, char *argv[]) {
+  std::vector<unsigned char> image;
+  unsigned w, h;
+  std::vector<unsigned char> buffer;
+  unsigned error;
+
+  //check if user gave a filename
+  if(argc < 3) {
+    std::cout << "please provide in and out filename" << std::endl;
+    return 0;
+  }
+
+  lodepng::load_file(buffer, argv[1]);
+  error = lodepng::decode(image, w, h, buffer);
+
+  if(error) {
+    std::cout << "decoding error " << error << ": " << lodepng_error_text(error) << std::endl;
+    return 0;
+  }
+
+  size_t origsize = buffer.size();
+  std::cout << "Original size: " << origsize << " (" << (origsize / 1024) << "K)" << std::endl;
+  buffer.clear();
+
+  //Now encode as hard as possible with several filter types and window sizes
+
+  lodepng::State state;
+  state.encoder.filter_palette_zero = 0; //We try several filter types, including zero, allow trying them all on palette images too.
+  state.encoder.add_id = false; //Don't add LodePNG version chunk to save more bytes
+  state.encoder.text_compression = 1; //Not needed because we don't add text chunks, but this demonstrates another optimization setting
+  state.encoder.zlibsettings.nicematch = 258; //Set this to the max possible, otherwise it can hurt compression
+  state.encoder.zlibsettings.lazymatching = 1; //Definitely use lazy matching for better compression
+  state.encoder.zlibsettings.windowsize = 32768; //Use maximum possible window size for best compression
+
+  size_t bestsize = 0;
+  bool inited = false;
+
+  int beststrategy = 0;
+  LodePNGFilterStrategy strategies[4] = { LFS_ZERO, LFS_MINSUM, LFS_ENTROPY, LFS_BRUTE_FORCE };
+  std::string strategynames[4] = { "LFS_ZERO", "LFS_MINSUM", "LFS_ENTROPY", "LFS_BRUTE_FORCE" };
+
+  // min match 3 allows all deflate lengths. min match 6 is similar to "Z_FILTERED" of zlib.
+  int minmatches[2] = { 3, 6 };
+  int bestminmatch = 0;
+
+  int autoconverts[2] = { 0, 1 };
+  std::string autoconvertnames[2] = { "0", "1" };
+  int bestautoconvert = 0;
+
+  int bestblocktype = 0;
+
+  // Try out all combinations of everything
+  for(int i = 0; i < 4; i++)   //filter strategy
+  for(int j = 0; j < 2; j++)   //min match
+  for(int k = 0; k < 2; k++)   //block type (for small images only)
+  for(int l = 0; l < 2; l++) { //color convert strategy
+    if(bestsize > 3000 && (k > 0 || l > 0)) continue; /* these only make sense on small images */
+    std::vector<unsigned char> temp;
+    state.encoder.filter_strategy = strategies[i];
+    state.encoder.zlibsettings.minmatch = minmatches[j];
+    state.encoder.zlibsettings.btype = k == 0 ? 2 : 1;
+    state.encoder.auto_convert = autoconverts[l];
+    error = lodepng::encode(temp, image, w, h, state);
+
+    if(error)
+    {
+      std::cout << "encoding error " << error << ": " << lodepng_error_text(error) << std::endl;
+      return 0;
+    }
+
+    if(!inited || temp.size() < bestsize)
+    {
+      bestsize = temp.size();
+      beststrategy = i;
+      bestminmatch = state.encoder.zlibsettings.minmatch;
+      bestautoconvert = l;
+      bestblocktype = state.encoder.zlibsettings.btype;
+      temp.swap(buffer);
+      inited = true;
+    }
+  }
+
+  std::cout << "Chosen filter strategy: " << strategynames[beststrategy] << std::endl;
+  std::cout << "Chosen min match: " << bestminmatch << std::endl;
+  std::cout << "Chosen block type: " << bestblocktype << std::endl;
+  std::cout << "Chosen auto convert: " << autoconvertnames[bestautoconvert] << std::endl;
+
+  lodepng::save_file(buffer, argv[2]);
+  std::cout << "New size: " << buffer.size() << " (" << (buffer.size() / 1024) << "K)" << std::endl;
+}