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 92

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

	Data_Get_Struct(self, struct readerdata, reader);

	if (reader->info) {
		png_destroy_read_struct(&reader->png, &reader->info, NULL);
		allocate2(reader);
		reader->locked = 0;
	}

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

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

	reader->scale_width = png_get_image_width(reader->png, reader->info);
	reader->scale_height = png_get_image_height(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 296

static VALUE each(int argc, VALUE *argv, VALUE self)
{
	struct readerdata *reader;
	png_infop winfo;
	png_structp wpng;
	VALUE opts;
	int cmp, state;
	struct each_args args;
	uint32_t i, height;
	png_byte ctype;
	unsigned char **scanlines;
	size_t row_bytes;

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

	Data_Get_Struct(self, struct readerdata, reader);

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

	wpng = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL,
		(png_error_ptr)error, (png_error_ptr)warning);
	winfo = png_create_info_struct(wpng);
	png_set_write_fn(wpng, 0, write_data_fn, flush_data_fn);

	cmp = png_get_channels(reader->png, reader->info);
	ctype = png_get_color_type(reader->png, reader->info);

	png_set_IHDR(wpng, winfo, reader->scale_width, reader->scale_height, 8,
		ctype, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT,
		PNG_FILTER_TYPE_DEFAULT);

	height = png_get_image_height(reader->png, reader->info);
	row_bytes = png_get_rowbytes(reader->png, reader->info);

	args.reader = reader;
	args.wpng = wpng;
	args.winfo = winfo;
	args.inwidthbuf = malloc(row_bytes);
	args.outwidthbuf = malloc(reader->scale_width * cmp);

	if (png_get_interlace_type(reader->png, reader->info) == PNG_INTERLACE_NONE) {
		yscaler_init(&args.ys, height, reader->scale_height,
			reader->scale_width * cmp);
		rb_protect((VALUE(*)(VALUE))each_interlace_none, (VALUE)&args, &state);
		yscaler_free(&args.ys);
	} else {
		scanlines = malloc(height * sizeof(unsigned char *));
		for (i=0; i<height; i++) {
			scanlines[i] = malloc(row_bytes);
		}

		args.scanlines = scanlines;
		rb_protect((VALUE(*)(VALUE))each_interlace, (VALUE)&args, &state);

		for (i=0; i<height; i++) {
			free(scanlines[i]);
		}
		free(scanlines);
	}

	free(args.inwidthbuf);
	free(args.outwidthbuf);
	png_destroy_write_struct(&wpng, &winfo);

	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 139

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 186

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 201

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 154

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 169

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 125

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));
}