Mask.cpp

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// Copyright (c) 2008-2019 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#include "Mask.h"
 
#include "Exceptions.h"
 
#include "ReaderBase.h"
#include "ChunkReader.h"
#include "FFmpegReader.h"
#include "QtImageReader.h"
#include <omp.h>
 
#ifdef USE_IMAGEMAGICK
    #include "ImageReader.h"
#endif
 
using namespace openshot;

Mask::Mask() : reader(NULL), replace_image(false), needs_refresh(true) {
    // Init effect properties
    init_effect_details();
}
 
// Default constructor
Mask::Mask(ReaderBase *mask_reader, Keyframe mask_brightness, Keyframe mask_contrast) :
        reader(mask_reader), brightness(mask_brightness), contrast(mask_contrast), replace_image(false), needs_refresh(true)
{
    // Init effect properties
    init_effect_details();
}
 
// Init effect settings
void Mask::init_effect_details()
{
    InitEffectInfo();

    info.class_name = "Mask";
    info.name = "Alpha Mask / Wipe Transition";
    info.description = "Uses a grayscale mask image to gradually wipe / transition between 2 images.";
    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> Mask::GetFrame(std::shared_ptr<openshot::Frame> frame, int64_t frame_number) {
    // Get the mask image (from the mask reader)
    std::shared_ptr<QImage> frame_image = frame->GetImage();
 
    // Check if mask reader is open
    #pragma omp critical (open_mask_reader)
    {
        if (reader && !reader->IsOpen())
            reader->Open();
    }
 
    // No reader (bail on applying the mask)
    if (!reader)
        return frame;
 
    // Get mask image (if missing or different size than frame image)
    #pragma omp critical (open_mask_reader)
    {
        if (!original_mask || !reader->info.has_single_image || needs_refresh ||
            (original_mask && original_mask->size() != frame_image->size())) {
 
            // Only get mask if needed
            auto mask_without_sizing = std::make_shared<QImage>(
                *reader->GetFrame(frame_number)->GetImage());
 
            // Resize mask image to match frame size
            original_mask = std::make_shared<QImage>(
                mask_without_sizing->scaled(
                    frame_image->width(), frame_image->height(),
                    Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
        }
    }
 
    // Once we've done the necessary resizing, we no longer need to refresh again
    needs_refresh = false;
 
    // Grab raw pointers and dimensions one time
    unsigned char* pixels      = reinterpret_cast<unsigned char*>(frame_image->bits());
    unsigned char* mask_pixels = reinterpret_cast<unsigned char*>(original_mask->bits());
    int width                   = original_mask->width();
    int height                  = original_mask->height();
    int num_pixels              = width * height;  // total pixel count
 
    // Evaluate brightness and contrast keyframes just once
    double contrast_value   = contrast.GetValue(frame_number);
    double brightness_value = brightness.GetValue(frame_number);
 
    int brightness_adj = static_cast<int>(255 * brightness_value);
    float contrast_factor = 20.0f / std::max(0.00001f, 20.0f - static_cast<float>(contrast_value));
 
    // Iterate over every pixel in parallel
#pragma omp parallel for schedule(static)
    for (int i = 0; i < num_pixels; ++i)
    {
        int idx = i * 4;
 
        int R = mask_pixels[idx + 0];
        int G = mask_pixels[idx + 1];
        int B = mask_pixels[idx + 2];
        int A = mask_pixels[idx + 3];
 
        // Compute base gray, then apply brightness + contrast
        int gray = qGray(R, G, B);
        gray += brightness_adj;
        gray = static_cast<int>(contrast_factor * (gray - 128) + 128);
 
        // Clamp (A - gray) into [0, 255]
        int diff = A - gray;
        if (diff < 0) diff = 0;
        else if (diff > 255) diff = 255;
 
        // Calculate the % change in alpha
        float alpha_percent = static_cast<float>(diff) / 255.0f;
 
        // Set the alpha channel to the gray value
        if (replace_image) {
            // Replace frame pixels with gray value (including alpha channel)
            auto new_val = static_cast<unsigned char>(diff);
            pixels[idx + 0] = new_val;
            pixels[idx + 1] = new_val;
            pixels[idx + 2] = new_val;
            pixels[idx + 3] = new_val;
        } else {
            // Premultiplied RGBA → multiply each channel by alpha_percent
            pixels[idx + 0] = static_cast<unsigned char>(pixels[idx + 0] * alpha_percent);
            pixels[idx + 1] = static_cast<unsigned char>(pixels[idx + 1] * alpha_percent);
            pixels[idx + 2] = static_cast<unsigned char>(pixels[idx + 2] * alpha_percent);
            pixels[idx + 3] = static_cast<unsigned char>(pixels[idx + 3] * alpha_percent);
        }
 
    }
 
    // return the modified frame
    return frame;
}
 
// Generate JSON string of this object
std::string Mask::Json() const {
 
    // Return formatted string
    return JsonValue().toStyledString();
}
 
// Generate Json::Value for this object
Json::Value Mask::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();
    if (reader)
        root["reader"] = reader->JsonValue();
    else
        root["reader"] = Json::objectValue;
    root["replace_image"] = replace_image;
 
    // return JsonValue
    return root;
}
 
// Load JSON string into this object
void Mask::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 Mask::SetJsonValue(const Json::Value root) {
 
    // Set parent data
    EffectBase::SetJsonValue(root);
 
    // Set data from Json (if key is found)
    if (!root["replace_image"].isNull())
        replace_image = root["replace_image"].asBool();
    if (!root["brightness"].isNull())
        brightness.SetJsonValue(root["brightness"]);
    if (!root["contrast"].isNull())
        contrast.SetJsonValue(root["contrast"]);
    if (!root["reader"].isNull()) // does Json contain a reader?
    {
        #pragma omp critical (open_mask_reader)
        {
            // This reader has changed, so refresh cached assets
            needs_refresh = true;
 
            if (!root["reader"]["type"].isNull()) // does the reader Json contain a 'type'?
            {
                // Close previous reader (if any)
                if (reader) {
                    // Close and delete existing reader (if any)
                    reader->Close();
                    delete reader;
                    reader = NULL;
                }
 
                // Create new reader (and load properties)
                std::string type = root["reader"]["type"].asString();
 
                if (type == "FFmpegReader") {
 
                    // Create new reader
                    reader = new FFmpegReader(root["reader"]["path"].asString());
                    reader->SetJsonValue(root["reader"]);
 
    #ifdef USE_IMAGEMAGICK
                } else if (type == "ImageReader") {
 
                    // Create new reader
                    reader = new ImageReader(root["reader"]["path"].asString());
                    reader->SetJsonValue(root["reader"]);
    #endif
 
                } else if (type == "QtImageReader") {
 
                    // Create new reader
                    reader = new QtImageReader(root["reader"]["path"].asString());
                    reader->SetJsonValue(root["reader"]);
 
                } else if (type == "ChunkReader") {
 
                    // Create new reader
                    reader = new ChunkReader(root["reader"]["path"].asString(), (ChunkVersion) root["reader"]["chunk_version"].asInt());
                    reader->SetJsonValue(root["reader"]);
 
                }
            }
 
        }
    }
 
}
 
// Get all properties for a specific frame
std::string Mask::PropertiesJSON(int64_t requested_frame) const {
 
    // Generate JSON properties list
    Json::Value root = BasePropertiesJSON(requested_frame);
 
    // Add replace_image choices (dropdown style)
    root["replace_image"] = add_property_json("Replace Image", replace_image, "int", "", NULL, 0, 1, false, requested_frame);
    root["replace_image"]["choices"].append(add_property_choice_json("Yes", true, replace_image));
    root["replace_image"]["choices"].append(add_property_choice_json("No", false, replace_image));
 
    // 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, 0, 20, false, requested_frame);
 
    if (reader)
        root["reader"] = add_property_json("Source", 0.0, "reader", reader->Json(), NULL, 0, 1, false, requested_frame);
    else
        root["reader"] = add_property_json("Source", 0.0, "reader", "{}", NULL, 0, 1, false, requested_frame);
 
    // Return formatted string
    return root.toStyledString();
}