refactored code

cc/BUILD

@@ -3,5 +3,7 @@ cc_binary(
     name = "svg-to-ascii",
     srcs = glob(["*.cc"]),
     visibility = ["//visibility:public"],
-    deps=["//thirdparty/nanosvg"],
+    deps=[
+        "//cc/ascii",
+    ],
 )

cc/ascii/BUILD

@@ -0,0 +1,10 @@
+cc_library(
+    visibility = ["//visibility:public"],
+    name = "ascii",
+    hdrs = glob(["*.hh"]),
+    srcs = glob(["*.cc"]),
+    includes = [""],
+    deps = [
+        "//thirdparty/nanosvg",
+    ]
+)

cc/ascii/ascii.cc

@@ -0,0 +1,157 @@
+#include "ascii.hh"
+#include <stdio.h>
+#include <math.h>
+#define NANOSVG_IMPLEMENTATION	// Expands implementation
+#define NANOSVG_CPLUSPLUS
+#define NANOSVGRAST_CPLUSPLUS
+#define NANOSVGRAST_IMPLEMENTATION
+#include "nanosvg.h"
+#include "nanosvgrast.h"
+
+// Convert RGB24 to xterm-256 8-bit value
+// For simplicity, assume RGB space is perceptually uniform.
+// There are 5 places where one of two outputs needs to be chosen when the
+// input is the exact middle:
+// - The r/g/b channels and the gray value: the higher value output is chosen.
+// - If the gray and color have same distance from the input - color is chosen.
+static unsigned char rgb_to_x256(uint8_t r, uint8_t g, uint8_t b)
+{
+    // Calculate the nearest 0-based color index at 16 .. 231
+#   define v2ci(v) (v < 48 ? 0 : v < 115 ? 1 : (v - 35) / 40)
+    int ir = v2ci(r), ig = v2ci(g), ib = v2ci(b);   // 0..5 each
+#   define color_index() (36 * ir + 6 * ig + ib)  /* 0..215, lazy evaluation */
+
+    // Calculate the nearest 0-based gray index at 232 .. 255
+    int average = (r + g + b) / 3;
+    int gray_index = average > 238 ? 23 : (average - 3) / 10;  // 0..23
+
+    // Calculate the represented colors back from the index
+    static const int i2cv[6] = {0, 0x5f, 0x87, 0xaf, 0xd7, 0xff};
+    int cr = i2cv[ir], cg = i2cv[ig], cb = i2cv[ib];  // r/g/b, 0..255 each
+    int gv = 8 + 10 * gray_index;  // same value for r/g/b, 0..255
+
+    // Return the one which is nearer to the original input rgb value
+#   define dist_square(A,B,C, a,b,c) ((A-a)*(A-a) + (B-b)*(B-b) + (C-c)*(C-c))
+    int color_err = dist_square(cr, cg, cb, r, g, b);
+    int gray_err  = dist_square(gv, gv, gv, r, g, b);
+    return color_err <= gray_err ? 16 + color_index() : 232 + gray_index;
+}
+
+void calcWeit(const unsigned char* rgbaImage, unsigned long widthStride, Rect rect, unsigned char& r, unsigned char& g, unsigned char& b) {
+  unsigned long long sr = 0;
+  unsigned long long sg = 0;
+  unsigned long long sb = 0;
+  const unsigned char* pixel; 
+  for(unsigned long x = rect.x; x < rect.x+rect.w; ++x) { 
+    for(unsigned long y = rect.y; y < rect.y+rect.h; ++y) {
+      pixel = rgbaImage + (x * 4 + y * widthStride);
+      sr += *(pixel++);
+      sg += *(pixel++);
+      sb += *(pixel++);
+    }  
+  }
+  sr /= rect.w * rect.h;
+  sg /= rect.w * rect.h;
+  sb /= rect.w * rect.h;
+  r = (unsigned char)sr;
+  g = (unsigned char)sg;
+  b = (unsigned char)sb;
+}
+
+void AsciiImage::render(const unsigned char* img, unsigned long width, unsigned long height) {
+  const std::string ASCII = " @B#Q80Rg&D$OEN9bd6MHWA%GpPSq5UZ4K3hkfmCFaVeoIs2jtJwzynu1YclT7}{Lxiv[]/\\()|?*r^<>+;~!=\",_-'  ";
+  unsigned long w = width;
+  unsigned long h = height/2;
+  unsigned long rw = width / w;
+  unsigned long rh = height / h;
+  unsigned char r, g, b;
+  unsigned char color;
+  unsigned int ind;
+  Rect rect;
+  float weit;
+  unsigned long position;
+  for(unsigned long y = 0; y < h; ++y) {
+    if ((y+1)*rh > height) {
+      break;
+    }
+    for(unsigned long x = 0; x < w; ++x) {
+      if ((x+1)*rw > width) {
+	break;
+      }
+      position = x + y * w;
+      rect.x = x * rw;
+      rect.y = y * rh;
+      rect.w = rw;
+      rect.h = rh;
+
+      calcWeit(img, width * 4, rect, r, g, b);
+
+      weit = ((float)(r + g + b)) / 3.0f / 255.0f;
+
+      weit = 1-weit;
+      weit = weit * weit;
+      weit = 1-weit;
+      color = rgb_to_x256(r, g, b);
+      ind = weit * (ASCII.size() - 1);
+      colors[position] = color;
+      text[position] = ASCII[ind];
+      //printf("\x1B[38;5;%im%c\x1B[0m", color, ASCII[ind]);
+    }
+    //printf("\n");
+  }
+  //fflush(stdout);
+}
+
+void AsciiImage::load() {
+  struct NSVGimage* image;
+  float scalex, scaley;
+  image = nsvgParseFromFile(path.c_str(), "px", 96);
+  if (image == NULL) {
+    printf("Error loading image %s\n", path.c_str());
+    unload();
+    return;
+  }
+
+  if (respect_width) {
+    width = image->width;
+    rect.w = width;
+  } else {
+    width = rect.w;
+  }
+
+  scalex = ((float)width)/image->width;
+
+  if (respect_height) {
+    scaley = scalex;
+    if (image->width == image->height) {
+      height = width;
+    } else {
+      height = scaley*image->height;
+    }
+    rect.h = height / 2;
+  } else {
+    height = rect.h * 2;
+    scaley = ((float)height)/image->height;
+  }
+  text = new unsigned char[rect.w * rect.h];
+  colors = new unsigned char[rect.w * rect.h];
+  // Rasterize
+  unsigned char* img = new unsigned char[width*height*4];
+  NSVGrasterizer* rast = nsvgCreateRasterizer();
+  nsvgRasterizeStretched(rast, image, 0,0,scalex, scaley, img, width, height, width*4);
+  nsvgDeleteRasterizer(rast);
+  render(img, width, height);
+  delete[] img;
+}
+
+void AsciiImage::print() {
+  unsigned long position;
+  for(unsigned long y = 0; y < rect.h; ++y) {
+    for(unsigned long x = 0; x < rect.w; ++x) {
+      position = x + y * rect.w;
+      printf("\x1B[38;5;%im%c\x1B[0m", colors[position], text[position]);
+    }
+    printf("\n");
+  }
+  fflush(stdout);
+}

cc/ascii/ascii.hh

@@ -0,0 +1,48 @@
+#pragma once
+#include <string>
+#include <stdlib.h>
+
+struct Rect {
+  unsigned long x,y,w,h;
+};
+
+class AsciiImage {
+ private:
+  bool respect_width;
+  bool respect_height;
+  Rect rect;
+  unsigned long width;
+  unsigned long height;
+  std::string path;
+  unsigned char* text = NULL;
+  unsigned char* colors = NULL;
+
+  void render(const unsigned char* image, unsigned long width, unsigned long height);
+
+ public:
+  AsciiImage(std::string path, Rect rect, bool respect_width, bool respect_height): respect_width(respect_width), respect_height(respect_height), rect(rect), width(rect.w), height(rect.h), path(path) {
+    load();
+  }
+
+  ~AsciiImage() {
+    unload();
+  }
+
+  void load();
+  void print();
+
+  void unload() {
+    if(text !=NULL){
+      delete[] text;
+    }
+
+    if (colors != NULL) {
+      delete[] colors;
+    }
+
+    text = NULL;
+    colors = NULL;
+  }
+};
+
+static unsigned char rgb_to_x256(uint8_t r, uint8_t g, uint8_t b);

cc/main.cc

@@ -1,146 +1,25 @@
+#include <stdlib.h>
 #include <stdio.h>
-#include <string.h>
-#include <string>
-#include <math.h>
-#define NANOSVG_IMPLEMENTATION	// Expands implementation
-#define NANOSVG_CPLUSPLUS
-#define NANOSVGRAST_CPLUSPLUS
-#define NANOSVGRAST_IMPLEMENTATION
-#include "nanosvg.h"
-#include "nanosvgrast.h"
-
-struct Rect {
-  unsigned long x,y,w,h;
-};
-
-// Convert RGB24 to xterm-256 8-bit value
-// For simplicity, assume RGB space is perceptually uniform.
-// There are 5 places where one of two outputs needs to be chosen when the
-// input is the exact middle:
-// - The r/g/b channels and the gray value: the higher value output is chosen.
-// - If the gray and color have same distance from the input - color is chosen.
-static int rgb_to_x256(uint8_t r, uint8_t g, uint8_t b)
-{
-    // Calculate the nearest 0-based color index at 16 .. 231
-#   define v2ci(v) (v < 48 ? 0 : v < 115 ? 1 : (v - 35) / 40)
-    int ir = v2ci(r), ig = v2ci(g), ib = v2ci(b);   // 0..5 each
-#   define color_index() (36 * ir + 6 * ig + ib)  /* 0..215, lazy evaluation */
-
-    // Calculate the nearest 0-based gray index at 232 .. 255
-    int average = (r + g + b) / 3;
-    int gray_index = average > 238 ? 23 : (average - 3) / 10;  // 0..23
-
-    // Calculate the represented colors back from the index
-    static const int i2cv[6] = {0, 0x5f, 0x87, 0xaf, 0xd7, 0xff};
-    int cr = i2cv[ir], cg = i2cv[ig], cb = i2cv[ib];  // r/g/b, 0..255 each
-    int gv = 8 + 10 * gray_index;  // same value for r/g/b, 0..255
-
-    // Return the one which is nearer to the original input rgb value
-#   define dist_square(A,B,C, a,b,c) ((A-a)*(A-a) + (B-b)*(B-b) + (C-c)*(C-c))
-    int color_err = dist_square(cr, cg, cb, r, g, b);
-    int gray_err  = dist_square(gv, gv, gv, r, g, b);
-    return color_err <= gray_err ? 16 + color_index() : 232 + gray_index;
-}
-
-void calcWeit(unsigned char* rgbaImage, unsigned long widthStride, Rect rect, unsigned char& r, unsigned char& g, unsigned char& b) {
-  unsigned long long sr = 0;
-  unsigned long long sg = 0;
-  unsigned long long sb = 0;
-  unsigned char* pixel; 
-  for(unsigned long x = rect.x; x < rect.x+rect.w; ++x) { 
-    for(unsigned long y = rect.y; y < rect.y+rect.h; ++y) {
-      pixel = rgbaImage + (x * 4 + y * widthStride);
-      sr += *(pixel++);
-      sg += *(pixel++);
-      sb += *(pixel++);
-    }  
-  }
-  sr /= rect.w * rect.h;
-  sg /= rect.w * rect.h;
-  sb /= rect.w * rect.h;
-  r = (unsigned char)sr;
-  g = (unsigned char)sg;
-  b = (unsigned char)sb;
-}
-
-void printArt(unsigned char* img, unsigned long width, unsigned long height) {
-  const std::string ASCII = " @B#Q80Rg&D$OEN9bd6MHWA%GpPSq5UZ4K3hXkfmCFaVeoIs2jtJwzynu1YclT7}{Lxiv[]/\\()|?*r^<>+;~!=\",_-'  ";
-  unsigned long w = width;
-  unsigned long h = height/2;
-  unsigned long rw = width / w;
-  unsigned long rh = height / h;
-  unsigned char r, g, b;
-  unsigned char color;
-  unsigned int ind;
-  Rect rect;
-  float weit;
-  for(unsigned long y = 0; y < h; ++y) {
-    if ((y+1)*rh > height) {
-      break;
-    }
-    for(unsigned long x = 0; x < w; ++x) {
-      if ((x+1)*rw > width) {
-	break;
-      }
-      rect.x = x * rw;
-      rect.y = y * rh;
-      rect.w = rw;
-      rect.h = rh;
-
-      calcWeit(img, width * 4, rect, r, g, b);
-
-      weit = ((float)(r + g + b)) / 3.0f / 255.0f;
-
-      weit = 1-weit;
-      weit = weit * weit;
-      weit = 1-weit;
-      color = rgb_to_x256(r, g, b);
-      ind = weit * (ASCII.size() - 1);
-      printf("\x1B[38;5;%im%c\x1B[0m", color, ASCII[ind]);
-    }
-    printf("\n");
-  }
-  fflush(stdout);
-}
+#include "ascii.hh"
 
 int main(int argc, char** argv) {
-  struct NSVGimage* image;
-  unsigned long w, h;
-  float scalex, scaley;
+  unsigned long w = 0, h = 0;
   if (argc < 2) {
     printf("Usage: %s <svg filename> [<width> [<height>]]\n", argv[0]);
     return 1;
   }
-  image = nsvgParseFromFile(argv[1], "px", 96);
-  if (image == NULL) {
-    printf("Error loading image %s\n", argv[1]);
-    return 1;
-  }
-
-  if (argc < 3) {
-    w = image->width;
-  } else {
+
+  if (argc > 2) {
     w = atoi(argv[2]);
   }
-  scalex = ((float)w)/image->width;
-
-  if (argc < 4) {
-    scaley = scalex;
-    if (image->width == image->height) {
-      h = w;
-    } else {
-      h = scaley*image->height;
-    }
-  } else {
+
+  if (argc > 3) {
     h = atoi(argv[3]);
-    scaley = ((float)h)/image->height;
   }
-  // Rasterize
-  unsigned char* img = new unsigned char[w*h*4];
-  NSVGrasterizer* rast = nsvgCreateRasterizer();
-  nsvgRasterizeStretched(rast, image, 0,0,scalex, scaley, img, w, h, w*4);
-  nsvgDeleteRasterizer(rast);
-  printArt(img, w, h);
-  delete[] img;
+
+  Rect r = {0, 0, w, h/2};
+  AsciiImage image(argv[1], r, argc < 3, argc < 4);
+  image.print();
+
   return 0;
 }