RGB to RGBA Color Conversion#

Converts an image from RGB to RGBA format.

Description

This function can operate with ROI (see Image Regions of Interest).

This function performs conversion from RGB image to RGBA image leaving pixel values unchanged, only changing number of channels from 3 channels to 4 channels. Alpha channel is filled with alpha_value from spec.

Headers

oneapi/ipl/convert.hpp

Syntax

template<typename SrcImageT, typename DstImageT>
sycl::event oneapi::ipl::rgb_to_rgba(sycl::queue &queue, SrcImageT &src, DstImageT &dst, const color_conversion_spec<typename DstImageT::data_t> &spec = {}, const std::vector<sycl::event> &dependencies = {})#

Function for RGB to RGBA color conversion.

Template Parameters

  • SrcImageT – Source image type

  • DstImageT – Destination image type

Parameters

  • queue – SYCL queue object

  • src – Source image object

  • dst – Destination image object

  • spec – Specification for convert function

  • dependencies – SYCL event dependencies

Returns

SYCL event

Parameters

See Parameters of Color Conversion (spec).

Errors

compile-time data type check

Indicates an error when image data type is not supported.

invalid_argument exception

Indicates an error when ROI sizes of the source image and the destination image are not equal.

invalid_argument exception

Indicates an error when one of the pitch values is not divisible by size of component data type in bytes.

The code example below demonstrates how shall be called oneapi::ipl::rgb_to_rgba for RGB to RGBA conversion:

using namespace oneapi;

sycl::queue                 queue;
ipl::shared_usm_allocator_t allocator{ queue };
const sycl::range<2>        image_size{ height, width };

// Source image for RGB data
ipl::image<ipl::layouts::channel3, std::uint8_t> src_image{ queue, p_image_data, image_size, allocator };
// Destination image for RGBA data
ipl::image<ipl::layouts::channel4, std::uint8_t> dst_image{ image_size, allocator };

ipl::color_conversion_spec<std::uint8_t> spec{ 255 };

// Convert RGB to RGBA with alpha value = 255
auto event = ipl::rgb_to_rgba(queue, src_image, dst_image, spec);