PixelOperations.h

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// SPDX-FileCopyrightText: 2026 Valentin Eloy
// SPDX-License-Identifier: GPL-3.0-or-later
 
#pragma once
 
#include <cstdint>
#include <optional>
#include <vector>
 
#include "HMI/Graphics/TextureLoader.h"

 
namespace hmi {

struct PixelRegion {
    int minX = 0;
    int minY = 0;
    int maxX = -1;  
    int maxY = -1;

    [[nodiscard]] constexpr bool empty() const noexcept {
        return maxX < minX || maxY < minY;
    }

    [[nodiscard]] constexpr int width() const noexcept {
        return empty() ? 0 : (maxX - minX + 1);
    }

    [[nodiscard]] constexpr int height() const noexcept {
        return empty() ? 0 : (maxY - minY + 1);
    }

    [[nodiscard]] constexpr bool operator==(const PixelRegion& other) const noexcept {
        return (empty() && other.empty()) || (minX == other.minX && minY == other.minY &&
                                              maxX == other.maxX && maxY == other.maxY);
    }
};

[[nodiscard]] constexpr bool pixelInBounds(int width, int height, int x, int y) noexcept {
    return x >= 0 && y >= 0 && x < width && y < height;
}

[[nodiscard]] constexpr PixelRegion unionPixelRegion(const PixelRegion& a,
                                                     const PixelRegion& b) noexcept {
    if (a.empty()) {
        return b;
    }
    if (b.empty()) {
        return a;
    }
    return PixelRegion{
        a.minX < b.minX ? a.minX : b.minX,
        a.minY < b.minY ? a.minY : b.minY,
        a.maxX > b.maxX ? a.maxX : b.maxX,
        a.maxY > b.maxY ? a.maxY : b.maxY,
    };
}

PixelRegion setPixel(DecodedImage& image, int x, int y, std::uint32_t color);

PixelRegion erasePixel(DecodedImage& image, int x, int y);

PixelRegion drawLine(DecodedImage& image, int x0, int y0, int x1, int y1, std::uint32_t color);

PixelRegion eraseLine(DecodedImage& image, int x0, int y0, int x1, int y1);

PixelRegion floodFill(DecodedImage& image, int x, int y, std::uint32_t color);

[[nodiscard]] std::optional<std::uint32_t> pickColor(const DecodedImage& image, int x,
                                                     int y) noexcept;

[[nodiscard]] std::vector<std::uint32_t> readRegion(const DecodedImage& image,
                                                    const PixelRegion& region);

void writeRegion(DecodedImage& image, const PixelRegion& region,
                 const std::vector<std::uint32_t>& data);

struct PixelClipboard {
    int width = 0;
    int height = 0;
    std::vector<std::uint32_t> pixels;

    [[nodiscard]] bool empty() const noexcept {
        return width <= 0 || height <= 0;
    }
};

PixelRegion flipHorizontal(DecodedImage& image, const PixelRegion& region);

PixelRegion flipVertical(DecodedImage& image, const PixelRegion& region);

PixelRegion rotateClockwise(DecodedImage& image, const PixelRegion& region);

PixelRegion rotateCounterClockwise(DecodedImage& image, const PixelRegion& region);

PixelRegion moveRegion(DecodedImage& image, const PixelRegion& region, int dx, int dy);

[[nodiscard]] PixelClipboard copyRegion(const DecodedImage& image, const PixelRegion& region);

PixelRegion pasteClipboard(DecodedImage& image, const PixelClipboard& clipboard, int x, int y);
 
}  // namespace hmi