Brightness.cpp

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// Copyright (c) 2008-2019 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#include "Brightness.h"
#include "Exceptions.h"
#include <array>
 
using namespace openshot;
 
Brightness::Brightness() : brightness(0.0), contrast(3.0), mask_mode(BRIGHTNESS_MASK_LIMIT_TO_AREA) {
    // Init effect properties
    init_effect_details();
}
 
// Default constructor
Brightness::Brightness(Keyframe new_brightness, Keyframe new_contrast) :
    brightness(new_brightness), contrast(new_contrast), mask_mode(BRIGHTNESS_MASK_LIMIT_TO_AREA)
{
    // Init effect properties
    init_effect_details();
}
 
// Init effect settings
void Brightness::init_effect_details()
{
    InitEffectInfo();
 
    info.class_name = "Brightness";
    info.name = "Brightness & Contrast";
    info.description = "Adjust the brightness and contrast of the frame's image.";
    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> Brightness::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;
 
    // Get keyframe values for this frame
    const float brightness_value = brightness.GetValue(frame_number);
    const float contrast_value = contrast.GetValue(frame_number);
    const float contrast_factor = (259.0f * (contrast_value + 255.0f)) / (255.0f * (259.0f - contrast_value));
    const int brightness_offset_i = static_cast<int>(255.0f * brightness_value);
 
    // Loop through pixels
    unsigned char *pixels = reinterpret_cast<unsigned char *>(frame_image->bits());
    const int pixel_count = frame_image->width() * frame_image->height();
    // 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_u8 = [](int value) -> unsigned char {
        if (value < 0) return 0;
        if (value > 255) return 255;
        return static_cast<unsigned char>(value);
    };
    const auto clamp_i = [](int value) -> int {
        if (value < 0) return 0;
        if (value > 255) return 255;
        return value;
    };
 
    const auto adjust_contrast_and_brightness = [&](int &R, int &G, int &B) {
        R = clamp_u8(clamp_i(static_cast<int>((contrast_factor * (R - 128)) + 128.0f)) + brightness_offset_i);
        G = clamp_u8(clamp_i(static_cast<int>((contrast_factor * (G - 128)) + 128.0f)) + brightness_offset_i);
        B = clamp_u8(clamp_i(static_cast<int>((contrast_factor * (B - 128)) + 128.0f)) + brightness_offset_i);
    };
 
    #pragma omp parallel for if(pixel_count >= 16384) schedule(static)
    for (int pixel = 0; pixel < pixel_count; ++pixel)
    {
        const int idx = pixel * 4;
 
        // Split hot paths by alpha to avoid unnecessary premultiply/unpremultiply work.
        const int A = pixels[idx + 3];
        if (A <= 0)
            continue;
        int R = 0;
        int G = 0;
        int B = 0;
        if (A == 255) {
            R = pixels[idx + 0];
            G = pixels[idx + 1];
            B = pixels[idx + 2];
            adjust_contrast_and_brightness(R, G, B);
            pixels[idx + 0] = static_cast<unsigned char>(R);
            pixels[idx + 1] = static_cast<unsigned char>(G);
            pixels[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>(pixels[idx + 0] * inv_alpha_percent);
            G = static_cast<int>(pixels[idx + 1] * inv_alpha_percent);
            B = static_cast<int>(pixels[idx + 2] * inv_alpha_percent);
            adjust_contrast_and_brightness(R, G, B);
 
            // Pre-multiply alpha back into color channels
            pixels[idx + 0] = static_cast<unsigned char>(R * alpha_percent);
            pixels[idx + 1] = static_cast<unsigned char>(G * alpha_percent);
            pixels[idx + 2] = static_cast<unsigned char>(B * alpha_percent);
        }
    }
 
    // return the modified frame
    return frame;
}
 
bool Brightness::UseCustomMaskBlend(int64_t frame_number) const {
    (void) frame_number;
    return mask_mode == BRIGHTNESS_MASK_VARY_STRENGTH;
}
 
void Brightness::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 pixel_count = effected_image->width() * effected_image->height();
 
    if (mask_invert) {
        #pragma omp parallel for schedule(static)
        for (int i = 0; i < pixel_count; ++i) {
            const int idx = i * 4;
            float factor = static_cast<float>(qGray(mask_pixels[idx], mask_pixels[idx + 1], mask_pixels[idx + 2])) / 255.0f;
            factor = 1.0f - factor;
            factor = factor * factor;
            const float inverse = 1.0f - factor;
 
            effected_pixels[idx] = static_cast<unsigned char>(
                (original_pixels[idx] * inverse) + (effected_pixels[idx] * factor));
            effected_pixels[idx + 1] = static_cast<unsigned char>(
                (original_pixels[idx + 1] * inverse) + (effected_pixels[idx + 1] * factor));
            effected_pixels[idx + 2] = static_cast<unsigned char>(
                (original_pixels[idx + 2] * inverse) + (effected_pixels[idx + 2] * factor));
            effected_pixels[idx + 3] = original_pixels[idx + 3];
        }
    } else {
        #pragma omp parallel for schedule(static)
        for (int i = 0; i < pixel_count; ++i) {
            const int idx = i * 4;
            float factor = static_cast<float>(qGray(mask_pixels[idx], mask_pixels[idx + 1], mask_pixels[idx + 2])) / 255.0f;
            factor = factor * factor;
            const float inverse = 1.0f - factor;
 
            effected_pixels[idx] = static_cast<unsigned char>(
                (original_pixels[idx] * inverse) + (effected_pixels[idx] * factor));
            effected_pixels[idx + 1] = static_cast<unsigned char>(
                (original_pixels[idx + 1] * inverse) + (effected_pixels[idx + 1] * factor));
            effected_pixels[idx + 2] = static_cast<unsigned char>(
                (original_pixels[idx + 2] * inverse) + (effected_pixels[idx + 2] * factor));
            effected_pixels[idx + 3] = original_pixels[idx + 3];
        }
    }
}
 
// Generate JSON string of this object
std::string Brightness::Json() const {
 
    // Return formatted string
    return JsonValue().toStyledString();
}
 
// Generate Json::Value for this object
Json::Value Brightness::JsonValue() const {
 
    // Create root json object
    Json::Value root = EffectBase::JsonValue(); // get parent properties
    root["type"] = info.class_name;
    root["brightness"] = brightness.JsonValue();
    root["contrast"] = contrast.JsonValue();
    root["mask_mode"] = mask_mode;
 
    // return JsonValue
    return root;
}
 
// Load JSON string into this object
void Brightness::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 Brightness::SetJsonValue(const Json::Value root) {
 
    // Set parent data
    EffectBase::SetJsonValue(root);
 
    // Set data from Json (if key is found)
    if (!root["brightness"].isNull())
        brightness.SetJsonValue(root["brightness"]);
    if (!root["contrast"].isNull())
        contrast.SetJsonValue(root["contrast"]);
    if (!root["mask_mode"].isNull())
        mask_mode = root["mask_mode"].asInt();
}
 
// Get all properties for a specific frame
std::string Brightness::PropertiesJSON(int64_t requested_frame) const {
 
    // Generate JSON properties list
    Json::Value root = BasePropertiesJSON(requested_frame);
 
    // Keyframes
    root["brightness"] = add_property_json("Brightness", brightness.GetValue(requested_frame), "float", "", &brightness, -1.0, 1.0, false, requested_frame);
    root["contrast"] = add_property_json("Contrast", contrast.GetValue(requested_frame), "float", "", &contrast, -128, 128.0, 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", BRIGHTNESS_MASK_LIMIT_TO_AREA, mask_mode));
    root["mask_mode"]["choices"].append(add_property_choice_json("Vary Strength", BRIGHTNESS_MASK_VARY_STRENGTH, mask_mode));
 
    // Return formatted string
    return root.toStyledString();
}