gdalalg_raster_blend.h

/******************************************************************************
 *
 * Project:  GDAL
 * Purpose:  "blend" step of "raster pipeline"
 * Author:   Even Rouault <even dot rouault at spatialys.com>
 *
 ******************************************************************************
 * Copyright (c) 2025, Even Rouault <even dot rouault at spatialys.com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/
 
#ifndef GDALALG_RASTER_BLEND_INCLUDED
#define GDALALG_RASTER_BLEND_INCLUDED
 
#include "gdalalg_raster_pipeline.h"
 
 
/************************************************************************/
/*                           CompositionMode                            */
/************************************************************************/
 
enum class CompositionMode : unsigned
{
    SRC_OVER = 0,
    HSV_VALUE,
    MULTIPLY,
    SCREEN,
    OVERLAY,
    HARD_LIGHT,
    DARKEN,
    LIGHTEN,
    COLOR_DODGE,
    COLOR_BURN,
};
 
std::map<CompositionMode, std::string> CompositionModes();
 
std::string CompositionModeToString(CompositionMode mode);
 
std::vector<std::string> CompositionModesIdentifiers();
 
CompositionMode CompositionModeFromString(const std::string &str);
 
int MinBandCountForCompositionMode(CompositionMode mode);
 
int MaxBandCountForCompositionMode(CompositionMode mode);
 
bool BandCountIsCompatibleWithCompositionMode(int bandCount,
                                              CompositionMode mode);
 
/************************************************************************/
/*                       GDALRasterBlendAlgorithm                       */
/************************************************************************/
 
class GDALRasterBlendAlgorithm /* non final*/
    : public GDALRasterPipelineStepAlgorithm
{
  public:
    explicit GDALRasterBlendAlgorithm(bool standaloneStep = false);
 
    static constexpr const char *NAME = "blend";
    static constexpr const char *DESCRIPTION =
        "Blend/compose two raster datasets";
    static constexpr const char *HELP_URL = "/programs/gdal_raster_blend.html";
 
  private:
    bool RunStep(GDALPipelineStepRunContext &ctxt) override;
    bool ValidateGlobal();
 
    GDALArgDatasetValue m_overlayDataset{};
    CompositionMode m_operator{};
    std::string m_operatorIdentifier{};
    static constexpr int OPACITY_INPUT_RANGE = 100;
    int m_opacity = OPACITY_INPUT_RANGE;
    std::unique_ptr<GDALDataset, GDALDatasetUniquePtrReleaser> m_poTmpSrcDS{};
    std::unique_ptr<GDALDataset, GDALDatasetUniquePtrReleaser>
        m_poTmpOverlayDS{};
};
 
/************************************************************************/
/*                  GDALRasterBlendAlgorithmStandalone                  */
/************************************************************************/
 
class GDALRasterBlendAlgorithmStandalone final : public GDALRasterBlendAlgorithm
{
  public:
    GDALRasterBlendAlgorithmStandalone()
        : GDALRasterBlendAlgorithm(/* standaloneStep = */ true)
    {
    }
 
    ~GDALRasterBlendAlgorithmStandalone() override;
};
 
 
#endif /* GDALALG_RASTER_COLOR_MERGE_INCLUDED */