API changes

0.25.1 (2024-04-05)

• added gpujpeg_default_parameters() and gpujpeg_default_image_parameters() functions to initialize structs gpujpeg_parameters and gpujpeg_image_parameters as follows:

  struct gpujpeg_parameters params = gpujpeg_default_parameters();
  // not needed - gpujpeg_set_default_parameters(&params);
  struct gpujpeg_image_parameters params_image = gpujpeg_default_image_parameters();
  // not needed - gpujpeg_image_set_default_paramete(&params_image);
  

  This is more compact and allows eg. brace-or-equal initialization in C++ as well as following the always initialize rule. It also prevents the temptation to empty/zero/aggregate initialize the structs, like:

  struct gpujpeg_parameters params = { }; // bad - empty/zero initialization
  struct gpujpeg_parameters params = { .verbose = 1 }; // bad - empty/zero-initialized remaining members
  

0.23.0 - 0.25.0 (2024-04-05)

Rationale: the idea behind removing the comp_count from gpujpeg_image_parameters is to keep it simply for RAW (input for encoder, output for decoder) image properties, where the image component count is already defined by pixel_format. The comp_count now represents the JPEG internal parameter and it is strongly bound to gpujpeg_parameters::sampling_factor, both should be set by gpujpeg_parameters_chroma_subsampling(). The internal component count can be also different, eg. encoding/decoding grayscale from the color image.

Also, the encoder and decoder should require less tweaking (eg. no explicit configuration of pixel format for the decoder, which was requested for grayscale).

• removed deprecated gpujpeg_parameters_chroma_subsampling_42{0,2}
• removed comp_count from gpujpeg_image_parameters and moved to gpujpeg_parameters. The value should not be set manually, anyways as it is currently bound to subsampling and should be set by gpujpeg_parameters_chroma_subsampling (if needed)
• if the input pixel format is subsampled (eg. UYVY), and subsampling not set explicitly, encoded JPEG is using the same sampling rate
• struct decoder_output now contains param_image representing metadata of the image
• decoding doesn't require the explicit output format setting, in which case RGB is output (or grayscale for monochromatic JPEG); there are couple of format placeholders meant for automatic format selection depending on the input JPEG properties.
• gpujpeg_image_save_to_file can use .XXX placeholder for extension causing correct extension to be used depending if the color space is RGB or YCbCr. It can be used with command-line application as well (of course, useful mostly with "-N" parameter)
• GPUJPEG_444_U8_P012A and GPUJPEG_444_U8_P012Z formats are replaced with single GPUJPEG_4444_U8_P0123