Pixelate.cpp

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// Copyright (c) 2008-2019 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#include "Pixelate.h"
#include "Exceptions.h"
#include "Json.h"
 
#include <QImage>
#include <QPainter>
#include <QRect>
#include <QPoint>
 
#include <algorithm>
 
using namespace openshot;
 
namespace {
double clamp_margin(double value) {
    if (value < 0.0)
        return 0.0;
    if (value > 1.0)
        return 1.0;
    return value;
}
}
 
Pixelate::Pixelate() : pixelization(0.5), left(0.0), top(0.0), right(0.0), bottom(0.0),
    mask_mode(PIXELATE_MASK_LIMIT_TO_AREA) {
    // Init effect properties
    init_effect_details();
}
 
// Default constructor
Pixelate::Pixelate(Keyframe pixelization, Keyframe left, Keyframe top, Keyframe right, Keyframe bottom) :
    pixelization(pixelization), left(left), top(top), right(right), bottom(bottom),
    mask_mode(PIXELATE_MASK_LIMIT_TO_AREA)
{
    // Init effect properties
    init_effect_details();
}
 
// Init effect settings
void Pixelate::init_effect_details()
{
    InitEffectInfo();
 
    info.class_name = "Pixelate";
    info.name = "Pixelate";
    info.description = "Pixelate (increase or decrease) the number of visible pixels.";
    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>
Pixelate::GetFrame(std::shared_ptr<openshot::Frame> frame, int64_t frame_number)
{
    // Get the frame's image
    std::shared_ptr<QImage> frame_image = frame->GetImage();
 
    // Get current keyframe values
    double pixelization_value = std::min(pow(0.001, fabs(pixelization.GetValue(frame_number))), 1.0);
    double left_value = left.GetValue(frame_number);
    double top_value = top.GetValue(frame_number);
    double right_value = right.GetValue(frame_number);
    double bottom_value = bottom.GetValue(frame_number);
 
    if (pixelization_value > 0.0) {
        int w = frame_image->width();
        int h = frame_image->height();
        if (w <= 0 || h <= 0)
            return frame;
 
        // Define area we're working on in terms of a QRect with QMargins applied
        QRect area(QPoint(0,0), frame_image->size());
        area = area.marginsRemoved({
            int(clamp_margin(left_value) * w),
            int(clamp_margin(top_value) * h),
            int(clamp_margin(right_value) * w),
            int(clamp_margin(bottom_value) * h)
        });
        area = area.intersected(QRect(QPoint(0,0), frame_image->size()));
        if (area.isEmpty())
            return frame;
 
        int scale_to = (int) (area.width() * pixelization_value);
        if (scale_to < 1) {
            scale_to = 1; // Not less than one pixel
        }
        // Copy and scale pixels in area to be pixelated
        auto frame_scaled = frame_image->copy(area).scaledToWidth(scale_to, Qt::SmoothTransformation);
 
        // Draw pixelated image back over original
        QPainter painter(frame_image.get());
        painter.drawImage(area, frame_scaled);
        painter.end();
    }
 
    // return the modified frame
    return frame;
}
 
bool Pixelate::UseCustomMaskBlend(int64_t frame_number) const {
    (void) frame_number;
    return mask_mode == PIXELATE_MASK_VARY_STRENGTH;
}
 
void Pixelate::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();
 
    #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;
        if (mask_invert)
            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];
    }
}
 
// Generate JSON string of this object
std::string Pixelate::Json() const {
 
    // Return formatted string
    return JsonValue().toStyledString();
}
 
// Generate Json::Value for this object
Json::Value Pixelate::JsonValue() const {
 
    // Create root json object
    Json::Value root = EffectBase::JsonValue(); // get parent properties
    root["type"] = info.class_name;
    root["pixelization"] = pixelization.JsonValue();
    root["left"] = left.JsonValue();
    root["top"] = top.JsonValue();
    root["right"] = right.JsonValue();
    root["bottom"] = bottom.JsonValue();
    root["mask_mode"] = mask_mode;
 
    // return JsonValue
    return root;
}
 
// Load JSON string into this object
void Pixelate::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 Pixelate::SetJsonValue(const Json::Value root) {
 
    // Set parent data
    EffectBase::SetJsonValue(root);
 
    // Set data from Json (if key is found)
    if (!root["pixelization"].isNull())
        pixelization.SetJsonValue(root["pixelization"]);
    if (!root["left"].isNull())
        left.SetJsonValue(root["left"]);
    if (!root["top"].isNull())
        top.SetJsonValue(root["top"]);
    if (!root["right"].isNull())
        right.SetJsonValue(root["right"]);
    if (!root["bottom"].isNull())
        bottom.SetJsonValue(root["bottom"]);
    if (!root["mask_mode"].isNull())
        mask_mode = root["mask_mode"].asInt();
}
 
// Get all properties for a specific frame
std::string Pixelate::PropertiesJSON(int64_t requested_frame) const {
 
    // Generate JSON properties list
    Json::Value root = BasePropertiesJSON(requested_frame);
 
    // Keyframes
    root["pixelization"] = add_property_json("Pixelization", pixelization.GetValue(requested_frame), "float", "", &pixelization, 0.0, 0.9999, false, requested_frame);
    root["left"] = add_property_json("Margin: Left", left.GetValue(requested_frame), "float", "", &left, 0.0, 1.0, false, requested_frame);
    root["top"] = add_property_json("Margin: Top", top.GetValue(requested_frame), "float", "", &top, 0.0, 1.0, false, requested_frame);
    root["right"] = add_property_json("Margin: Right", right.GetValue(requested_frame), "float", "", &right, 0.0, 1.0, false, requested_frame);
    root["bottom"] = add_property_json("Margin: Bottom", bottom.GetValue(requested_frame), "float", "", &bottom, 0.0, 1.0, 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", PIXELATE_MASK_LIMIT_TO_AREA, mask_mode));
    root["mask_mode"]["choices"].append(add_property_choice_json("Vary Strength", PIXELATE_MASK_VARY_STRENGTH, mask_mode));
 
    // Return formatted string
    return root.toStyledString();
}