Module: OilyPNG::Resampling

Included in:
Canvas
Defined in:
ext/oily_png/oily_png_ext.c

Instance Method Summary collapse

Instance Method Details

#resample_bilinear!(v_new_width, v_new_height) ⇒ Object 



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# File 'ext/oily_png/resampling.c', line 155

VALUE oily_png_canvas_resample_bilinear_bang(VALUE self, VALUE v_new_width, VALUE v_new_height) {
  long new_width = NUM2LONG(v_new_width);
  long new_height = NUM2LONG(v_new_height);

  long self_width = NUM2LONG(rb_funcall(self, rb_intern("width"), 0));
  long self_height = NUM2LONG(rb_funcall(self, rb_intern("height"), 0));

  VALUE pixels = rb_ary_new2(new_width*new_height);
  VALUE source = rb_iv_get(self, "@pixels");

  long *index_x = ALLOC_N(long, new_width);
  long *index_y = ALLOC_N(long, new_height);
  long *interp_x = ALLOC_N(long, new_width);
  long *interp_y = ALLOC_N(long, new_height);

  oily_png_generate_steps_residues(self_width, new_width, index_x, interp_x);
  oily_png_generate_steps_residues(self_height, new_height, index_y, interp_y);

  long index = 0;
  long x, y;
  long y1, y2, x1, x2;
  PIXEL y_residue, x_residue;
  PIXEL pixel_11, pixel_21, pixel_12, pixel_22;
  PIXEL pixel_top, pixel_bot;
  for (y = 0; y < new_height; y++) {
    y1 = index_y[y] < 0 ? 0 : index_y[y];
    y2 = index_y[y]+1 >= self_height ? self_height-1 : index_y[y]+1;
    y_residue = interp_y[y];

    for (x = 0; x < new_width; x++) {
      x1 = index_x[x] < 0 ? 0 : index_x[x];
      x2 = index_x[x]+1 >= self_width ? self_width-1 : index_x[x]+1;
      x_residue = interp_x[x];

      pixel_11 = NUM2UINT(rb_ary_entry(source, y1*self_width + x1));
      pixel_21 = NUM2UINT(rb_ary_entry(source, y1*self_width + x2));
      pixel_12 = NUM2UINT(rb_ary_entry(source, y2*self_width + x1));
      pixel_22 = NUM2UINT(rb_ary_entry(source, y2*self_width + x2));

      pixel_top = oily_png_color_interpolate_quick(pixel_21, pixel_11, x_residue);
      pixel_bot = oily_png_color_interpolate_quick(pixel_22, pixel_12, x_residue);

      rb_ary_store(pixels, index++, UINT2NUM(oily_png_color_interpolate_quick(pixel_bot, pixel_top, y_residue)));
    }
  }

  xfree(index_x);
  xfree(index_y);
  xfree(interp_x);
  xfree(interp_y);
  interp_x = NULL;
  interp_y = NULL;

  rb_iv_set(self, "@pixels", pixels);
  rb_iv_set(self, "@width", LONG2NUM(new_width));
  rb_iv_set(self, "@height", LONG2NUM(new_height));

  return self;
}

#resample_nearest_neighbor!(v_new_width, v_new_height) ⇒ Object 



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# File 'ext/oily_png/resampling.c', line 114

VALUE oily_png_canvas_resample_nearest_neighbor_bang(VALUE self, VALUE v_new_width, VALUE v_new_height) {
  long new_width = NUM2LONG(v_new_width);
  long new_height = NUM2LONG(v_new_height);

  long self_width = NUM2LONG(rb_funcall(self, rb_intern("width"), 0));
  long self_height = NUM2LONG(rb_funcall(self, rb_intern("height"), 0));

  VALUE pixels = rb_ary_new2(new_width*new_height);
  VALUE source = rb_iv_get(self, "@pixels");

  long *steps_x = ALLOC_N(long, new_width);
  long *steps_y = ALLOC_N(long, new_height);

  oily_png_generate_steps_residues(self_width, new_width, steps_x, NULL);
  oily_png_generate_steps_residues(self_height, new_height, steps_y, NULL);

  long index = 0;
  long x, y;
  long src_index;
  for (y=0; y < new_height; y++) {
    for (x = 0; x < new_width; x++) {
      src_index = steps_y[y] * self_width + steps_x[x];
      VALUE pixel = rb_ary_entry(source, src_index);
      rb_ary_store(pixels, index, pixel);
      index++;
    }
  }

  xfree(steps_x);
  steps_x = NULL;

  xfree(steps_y);
  steps_y = NULL;

  rb_iv_set(self, "@pixels", pixels);
  rb_iv_set(self, "@width", LONG2NUM(new_width));
  rb_iv_set(self, "@height", LONG2NUM(new_height));

  return self;
}