Class: Oil::PNGReader

Inherits:
Object
  • Object
show all
Defined in:
ext/oil/png.c

Instance Method Summary collapse

Constructor Details

#initialize(io) ⇒ Object 



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# File 'ext/oil/png.c', line 85

static VALUE initialize(VALUE self, VALUE io)
{
  struct readerdata *reader;

  Data_Get_Struct(self, struct readerdata, reader);

  if (reader->source_io) {
    png_destroy_read_struct(&reader->png, &reader->info, NULL);
    reader->png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, (png_error_ptr)error, (png_error_ptr)warning);
    reader->locked = 0;
  }

  reader->source_io = io;
  reader->info = png_create_info_struct(reader->png);
  png_set_read_fn(reader->png, (void*)io, read_data);
  png_read_info(reader->png, reader->info);
  return self;
}

Instance Method Details

#each(opts, &block) ⇒ self

Yields a series of binary strings that make up the output JPEG image.

Options is a hash which may have the following symbols:

:quality - JPEG quality setting. Betweein 0 and 100. :markers - Custom markers to include in the output JPEG. Must be a hash where

the keys are :APP[0-15] or :COM and the values are arrays of strings that
will be inserted into the markers.

Returns:

  • (self) 


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# File 'ext/oil/png.c', line 261

static VALUE each(int argc, VALUE *argv, VALUE self)
{
  struct readerdata *reader;
  int cmp, state;
  struct write_png_args args;
  unsigned char *inwidthbuf, *outwidthbuf;
  struct yscaler ys;
  VALUE opts;
  png_structp png;
  png_infop info;

  rb_scan_args(argc, argv, "01", &opts);

  Data_Get_Struct(self, struct readerdata, reader);

  raise_if_locked(reader);
  reader->locked = 1;

  png_set_packing(reader->png);
  png_set_strip_16(reader->png);
  png_set_expand(reader->png);
  png_read_update_info(reader->png, reader->info);

  if (!reader->scale_width) {
    reader->scale_width = png_get_image_width(reader->png, reader->info);
  }
  if (!reader->scale_height) {
    reader->scale_height = png_get_image_height(reader->png, reader->info);
  }

  png = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL,
    (png_error_ptr)error, (png_error_ptr)warning);
  info = png_create_info_struct(png);

  inwidthbuf = malloc(png_get_rowbytes(reader->png, reader->info));
  cmp = png_get_channels(reader->png, reader->info);
  outwidthbuf = malloc(reader->scale_width * cmp);
  yscaler_init(&ys, png_get_image_height(reader->png, reader->info),
    reader->scale_height, reader->scale_width * cmp);

  args.reader = reader;
  args.opts = opts;
  args.png = png;
  args.info = info;
  args.inwidthbuf = inwidthbuf;
  args.outwidthbuf = outwidthbuf;
  args.ys = &ys;
  rb_protect((VALUE(*)(VALUE))each2, (VALUE)&args, &state);

  yscaler_free(&ys);
  free(inwidthbuf);
  free(outwidthbuf);
  png_destroy_write_struct(&png, &info);

  if (state) {
    rb_jump_tag(state);
  }

  return self;
}

#height ⇒ Numeric

Retrieve the height of the image.

Returns:

  • (Numeric) 


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# File 'ext/oil/png.c', line 125

static VALUE height(VALUE self)
{
  struct readerdata *reader;
  Data_Get_Struct(self, struct readerdata, reader);
  return INT2FIX(png_get_image_height(reader->png, reader->info));
}

#scale_height ⇒ Numeric

Retrieve the height to which the image will be resized after decompression. A height of 0 means the image will remain at original height.

Returns:

  • (Numeric) 


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# File 'ext/oil/png.c', line 172

static VALUE scale_height(VALUE self)
{
  struct readerdata *reader;
  Data_Get_Struct(self, struct readerdata, reader);
  return INT2FIX(reader->scale_height);
}

#scale_height=(number) ⇒ Object

Set the height to which the image will be resized after decompression. A height of 0 means the image will remain at original height.



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# File 'ext/oil/png.c', line 187

static VALUE set_scale_height(VALUE self, VALUE scale_height)
{
  struct readerdata *reader;
  Data_Get_Struct(self, struct readerdata, reader);
  raise_if_locked(reader);
  reader->scale_height = NUM2INT(scale_height);
  return scale_height;
}

#scale_width ⇒ Numeric

Retrieve the width to which the image will be resized after decompression. A width of 0 means the image will remain at original width.

Returns:

  • (Numeric) 


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# File 'ext/oil/png.c', line 140

static VALUE scale_width(VALUE self)
{
  struct readerdata *reader;
  Data_Get_Struct(self, struct readerdata, reader);
  return INT2FIX(reader->scale_width);
}

#scale_width=(number) ⇒ Object

Set the width to which the image will be resized after decompression. A width of 0 means the image will remain at original width.



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# File 'ext/oil/png.c', line 155

static VALUE set_scale_width(VALUE self, VALUE scale_width)
{
  struct readerdata *reader;
  Data_Get_Struct(self, struct readerdata, reader);
  raise_if_locked(reader);
  reader->scale_width = NUM2INT(scale_width);
  return scale_width;
}

#width ⇒ Numeric

Retrieve the width of the image.

Returns:

  • (Numeric) 


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# File 'ext/oil/png.c', line 111

static VALUE width(VALUE self)
{
  struct readerdata *reader;
  Data_Get_Struct(self, struct readerdata, reader);
  return INT2FIX(png_get_image_width(reader->png, reader->info));
}