Saturation.cpp

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// Copyright (c) 2008-2019 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#include "Saturation.h"
#include "Exceptions.h"
#include <array>
#include <cmath>
 
using namespace openshot;
 
Saturation::Saturation() : saturation(1.0), saturation_R(1.0), saturation_G(1.0), saturation_B(1.0),
    mask_mode(SATURATION_MASK_POST_BLEND) {
    // Init effect properties
    init_effect_details();
}
 
// Default constructor
Saturation::Saturation(Keyframe saturation, Keyframe saturation_R, Keyframe saturation_G, Keyframe saturation_B) :
        saturation(saturation), saturation_R(saturation_R), saturation_G(saturation_G), saturation_B(saturation_B),
        mask_mode(SATURATION_MASK_POST_BLEND)
{
    // Init effect properties
    init_effect_details();
}
 
bool Saturation::UseCustomMaskBlend(int64_t frame_number) const {
    (void) frame_number;
    return mask_mode == SATURATION_MASK_DRIVE_AMOUNT;
}
 
void Saturation::ApplyCustomMaskBlend(std::shared_ptr<QImage> original_image, std::shared_ptr<QImage> effected_image,
                                      std::shared_ptr<QImage> mask_image, int64_t frame_number) const {
    (void) frame_number;
    if (!original_image || !effected_image || !mask_image)
        return;
    if (original_image->size() != effected_image->size() || effected_image->size() != mask_image->size())
        return;
 
    unsigned char* original_pixels = reinterpret_cast<unsigned char*>(original_image->bits());
    unsigned char* effected_pixels = reinterpret_cast<unsigned char*>(effected_image->bits());
    unsigned char* mask_pixels = reinterpret_cast<unsigned char*>(mask_image->bits());
    const int width = effected_image->width();
    const int height = effected_image->height();
    const int original_stride = original_image->bytesPerLine();
    const int effected_stride = effected_image->bytesPerLine();
    const int mask_stride = mask_image->bytesPerLine();
 
    if (mask_invert) {
        #pragma omp parallel for schedule(static)
        for (int y = 0; y < height; ++y) {
            unsigned char* original_row = original_pixels + y * original_stride;
            unsigned char* effected_row = effected_pixels + y * effected_stride;
            unsigned char* mask_row = mask_pixels + y * mask_stride;
            for (int x = 0; x < width; ++x) {
                const int idx = x * 4;
                float factor = static_cast<float>(qGray(mask_row[idx], mask_row[idx + 1], mask_row[idx + 2])) / 255.0f;
                factor = 1.0f - factor;
                // Use a non-linear response curve for custom saturation drive mode.
                factor = factor * factor;
                const float inverse = 1.0f - factor;
 
                // Drive saturation strength with mask while preserving source alpha.
                effected_row[idx] = static_cast<unsigned char>(
                    (original_row[idx] * inverse) + (effected_row[idx] * factor));
                effected_row[idx + 1] = static_cast<unsigned char>(
                    (original_row[idx + 1] * inverse) + (effected_row[idx + 1] * factor));
                effected_row[idx + 2] = static_cast<unsigned char>(
                    (original_row[idx + 2] * inverse) + (effected_row[idx + 2] * factor));
                effected_row[idx + 3] = original_row[idx + 3];
            }
        }
    } else {
        #pragma omp parallel for schedule(static)
        for (int y = 0; y < height; ++y) {
            unsigned char* original_row = original_pixels + y * original_stride;
            unsigned char* effected_row = effected_pixels + y * effected_stride;
            unsigned char* mask_row = mask_pixels + y * mask_stride;
            for (int x = 0; x < width; ++x) {
                const int idx = x * 4;
                float factor = static_cast<float>(qGray(mask_row[idx], mask_row[idx + 1], mask_row[idx + 2])) / 255.0f;
                // Use a non-linear response curve for custom saturation drive mode.
                factor = factor * factor;
                const float inverse = 1.0f - factor;
 
                // Drive saturation strength with mask while preserving source alpha.
                effected_row[idx] = static_cast<unsigned char>(
                    (original_row[idx] * inverse) + (effected_row[idx] * factor));
                effected_row[idx + 1] = static_cast<unsigned char>(
                    (original_row[idx + 1] * inverse) + (effected_row[idx + 1] * factor));
                effected_row[idx + 2] = static_cast<unsigned char>(
                    (original_row[idx + 2] * inverse) + (effected_row[idx + 2] * factor));
                effected_row[idx + 3] = original_row[idx + 3];
            }
        }
    }
}
 
// Init effect settings
void Saturation::init_effect_details()
{
    InitEffectInfo();
 
    info.class_name = "Saturation";
    info.name = "Color Saturation";
    info.description = "Adjust the color saturation.";
    info.has_audio = false;
    info.has_video = true;
}
 
// This method is required for all derived classes of EffectBase, and returns a
// modified openshot::Frame object
std::shared_ptr<openshot::Frame> Saturation::GetFrame(std::shared_ptr<openshot::Frame> frame, int64_t frame_number)
{
    // Get the frame's image
    std::shared_ptr<QImage> frame_image = frame->GetImage();
 
    if (!frame_image)
        return frame;
 
    const int pixel_count = frame_image->width() * frame_image->height();
 
    // Get keyframe values for this frame
    const float saturation_value = saturation.GetValue(frame_number);
    const float saturation_value_R = saturation_R.GetValue(frame_number);
    const float saturation_value_G = saturation_G.GetValue(frame_number);
    const float saturation_value_B = saturation_B.GetValue(frame_number);
 
    // Constants used for color saturation formula
    const float pR = 0.299f;
    const float pG = 0.587f;
    const float pB = 0.114f;
    const float sqrt_pR = std::sqrt(pR);
    const float sqrt_pG = std::sqrt(pG);
    const float sqrt_pB = std::sqrt(pB);
    // Rec.601 fixed-point luma weights used in many image/video pipelines.
    // This avoids per-pixel sqrt() while keeping output stable.
    static const std::array<float, 65026> sqrt_lut = [] {
        std::array<float, 65026> lut{};
        for (int i = 0; i <= 65025; ++i)
            lut[i] = std::sqrt(static_cast<float>(i));
        return lut;
    }();
 
    // Loop through pixels
    unsigned char *pixels = reinterpret_cast<unsigned char *>(frame_image->bits());
    const int width = frame_image->width();
    const int height = frame_image->height();
    const int stride = frame_image->bytesPerLine();
    // LUT for undoing premultiplication without a per-pixel divide.
    static const std::array<float, 256> inv_alpha = [] {
        std::array<float, 256> lut{};
        lut[0] = 0.0f;
        for (int i = 1; i < 256; ++i)
            lut[i] = 255.0f / static_cast<float>(i);
        return lut;
    }();
    const auto clamp_i = [](int value) -> int {
        if (value < 0) return 0;
        if (value > 255) return 255;
        return value;
    };
 
    const auto apply_saturation = [&](int &R, int &G, int &B) {
        // Approximate sqrt(R^2*pR + G^2*pG + B^2*pB) with fixed-point weighted
        // intensity and lookup table. 77/150/29 ~= 0.299/0.587/0.114.
        const int weighted_sq = (77 * R * R + 150 * G * G + 29 * B * B + 128) >> 8;
        const float p = sqrt_lut[weighted_sq];
 
        // Adjust common saturation
        R = clamp_i(static_cast<int>(p + (R - p) * saturation_value));
        G = clamp_i(static_cast<int>(p + (G - p) * saturation_value));
        B = clamp_i(static_cast<int>(p + (B - p) * saturation_value));
 
        // Compute per-channel replacement brightness
        const float p_r = R * sqrt_pR;
        const float p_g = G * sqrt_pG;
        const float p_b = B * sqrt_pB;
 
        // Adjust channel-separated saturation
        const int Rr = static_cast<int>(p_r + (R - p_r) * saturation_value_R);
        const int Gr = static_cast<int>(p_r - p_r * saturation_value_R);
        const int Br = static_cast<int>(p_r - p_r * saturation_value_R);
 
        const int Rg = static_cast<int>(p_g - p_g * saturation_value_G);
        const int Gg = static_cast<int>(p_g + (G - p_g) * saturation_value_G);
        const int Bg = static_cast<int>(p_g - p_g * saturation_value_G);
 
        const int Rb = static_cast<int>(p_b - p_b * saturation_value_B);
        const int Gb = static_cast<int>(p_b - p_b * saturation_value_B);
        const int Bb = static_cast<int>(p_b + (B - p_b) * saturation_value_B);
 
        // Recombine and constrain values
        R = clamp_i(Rr + Rg + Rb);
        G = clamp_i(Gr + Gg + Gb);
        B = clamp_i(Br + Bg + Bb);
    };
 
    #pragma omp parallel for if(pixel_count >= 16384) schedule(static) shared (pixels)
    for (int y = 0; y < height; ++y)
    {
        unsigned char* row = pixels + y * stride;
        for (int x = 0; x < width; ++x) {
            const int idx = x * 4;
 
            // Split hot paths by alpha to avoid unnecessary premultiply/unpremultiply work.
            const int A = row[idx + 3];
            if (A <= 0)
                continue;
            int R = 0;
            int G = 0;
            int B = 0;
            if (A == 255) {
                R = row[idx + 0];
                G = row[idx + 1];
                B = row[idx + 2];
                apply_saturation(R, G, B);
                row[idx + 0] = static_cast<unsigned char>(R);
                row[idx + 1] = static_cast<unsigned char>(G);
                row[idx + 2] = static_cast<unsigned char>(B);
            } else {
                const float alpha_percent = static_cast<float>(A) * (1.0f / 255.0f);
                const float inv_alpha_percent = inv_alpha[A];
 
                // Get RGB values, and remove pre-multiplied alpha
                R = static_cast<int>(row[idx + 0] * inv_alpha_percent);
                G = static_cast<int>(row[idx + 1] * inv_alpha_percent);
                B = static_cast<int>(row[idx + 2] * inv_alpha_percent);
                apply_saturation(R, G, B);
 
                // Pre-multiply alpha back into color channels
                row[idx + 0] = static_cast<unsigned char>(R * alpha_percent);
                row[idx + 1] = static_cast<unsigned char>(G * alpha_percent);
                row[idx + 2] = static_cast<unsigned char>(B * alpha_percent);
            }
        }
    }
 
    // return the modified frame
    return frame;
}
 
// Generate JSON string of this object
std::string Saturation::Json() const {
 
    // Return formatted string
    return JsonValue().toStyledString();
}
 
// Generate Json::Value for this object
Json::Value Saturation::JsonValue() const {
 
    // Create root json object
    Json::Value root = EffectBase::JsonValue(); // get parent properties
    root["type"] = info.class_name;
    root["saturation"] = saturation.JsonValue();
    root["saturation_R"] = saturation_R.JsonValue();
    root["saturation_G"] = saturation_G.JsonValue();
    root["saturation_B"] = saturation_B.JsonValue();
    root["mask_mode"] = mask_mode;
 
    // return JsonValue
    return root;
}
 
// Load JSON string into this object
void Saturation::SetJson(const std::string value) {
 
    // Parse JSON string into JSON objects
    try
    {
        const Json::Value root = openshot::stringToJson(value);
        // Set all values that match
        SetJsonValue(root);
    }
    catch (const std::exception& e)
    {
        // Error parsing JSON (or missing keys)
        throw InvalidJSON("JSON is invalid (missing keys or invalid data types)");
    }
}
 
// Load Json::Value into this object
void Saturation::SetJsonValue(const Json::Value root) {
 
    // Set parent data
    EffectBase::SetJsonValue(root);
 
    // Set data from Json (if key is found)
    if (!root["saturation"].isNull())
        saturation.SetJsonValue(root["saturation"]);
    if (!root["saturation_R"].isNull())
        saturation_R.SetJsonValue(root["saturation_R"]);
    if (!root["saturation_G"].isNull())
        saturation_G.SetJsonValue(root["saturation_G"]);
    if (!root["saturation_B"].isNull())
        saturation_B.SetJsonValue(root["saturation_B"]);
    if (!root["mask_mode"].isNull())
        mask_mode = root["mask_mode"].asInt();
}
 
// Get all properties for a specific frame
std::string Saturation::PropertiesJSON(int64_t requested_frame) const {
 
    // Generate JSON properties list
    Json::Value root = BasePropertiesJSON(requested_frame);
 
    // Keyframes
    root["saturation"] = add_property_json("Saturation", saturation.GetValue(requested_frame), "float", "", &saturation, 0.0, 4.0, false, requested_frame);
    root["saturation_R"] = add_property_json("Saturation (Red)", saturation_R.GetValue(requested_frame), "float", "", &saturation_R, 0.0, 4.0, false, requested_frame);
    root["saturation_G"] = add_property_json("Saturation (Green)", saturation_G.GetValue(requested_frame), "float", "", &saturation_G, 0.0, 4.0, false, requested_frame);
    root["saturation_B"] = add_property_json("Saturation (Blue)", saturation_B.GetValue(requested_frame), "float", "", &saturation_B, 0.0, 4.0, false, requested_frame);
    root["mask_mode"] = add_property_json("Mask Mode", mask_mode, "int", "", NULL, 0, 1, false, requested_frame);
    root["mask_mode"]["choices"].append(add_property_choice_json("Limit to Mask", SATURATION_MASK_POST_BLEND, mask_mode));
    root["mask_mode"]["choices"].append(add_property_choice_json("Vary Strength", SATURATION_MASK_DRIVE_AMOUNT, mask_mode));
 
    // Return formatted string
    return root.toStyledString();
}