Hue.cpp

Go to the documentation of this file.

 
// Copyright (c) 2008-2019 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#include "Hue.h"
#include "Exceptions.h"
 
using namespace openshot;
 
Hue::Hue() : Hue(0.0) {
    // Init effect properties
    init_effect_details();
}
 
// Default constructor
Hue::Hue(Keyframe hue): hue(hue)
{
    // Init effect properties
    init_effect_details();
}
 
// Init effect settings
void Hue::init_effect_details()
{
    InitEffectInfo();
 
    info.class_name = "Hue";
    info.name = "Hue";
    info.description = "Adjust the hue / color 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> Hue::GetFrame(std::shared_ptr<openshot::Frame> frame, int64_t frame_number)
{
    // Get the frame's image
    std::shared_ptr<QImage> frame_image = frame->GetImage();
 
    int pixel_count = frame_image->width() * frame_image->height();
 
    // Get the current hue percentage shift amount, and convert to degrees
    double degrees = 360.0 * hue.GetValue(frame_number);
    float cosA = cos(degrees*3.14159265f/180);
    float sinA = sin(degrees*3.14159265f/180);
 
    // Calculate a rotation matrix for the RGB colorspace (based on the current hue shift keyframe value)
    float matrix[3] = {
        cosA + (1.0f - cosA) / 3.0f,
        1.0f/3.0f * (1.0f - cosA) - sqrtf(1.0f/3.0f) * sinA,
        1.0f/3.0f * (1.0f - cosA) + sqrtf(1.0f/3.0f) * sinA
    };
 
    // Loop through pixels
    unsigned char *pixels = (unsigned char *) frame_image->bits();
 
    #pragma omp parallel for shared (pixels)
    for (int pixel = 0; pixel < pixel_count; ++pixel)
    {
        // Calculate alpha % (to be used for removing pre-multiplied alpha value)
        int A = pixels[pixel * 4 + 3];
        float alpha_percent = A / 255.0;
 
        // Get RGB values, and remove pre-multiplied alpha
        int R = pixels[pixel * 4 + 0] / alpha_percent;
        int G = pixels[pixel * 4 + 1] / alpha_percent;
        int B = pixels[pixel * 4 + 2] / alpha_percent;
 
        // Multiply each color by the hue rotation matrix
        pixels[pixel * 4] = constrain(R * matrix[0] + G * matrix[1] + B * matrix[2]);
        pixels[pixel * 4 + 1] = constrain(R * matrix[2] + G * matrix[0] + B * matrix[1]);
        pixels[pixel * 4 + 2] = constrain(R * matrix[1] + G * matrix[2] + B * matrix[0]);
 
        // Pre-multiply the alpha back into the color channels
        pixels[pixel * 4 + 0] *= alpha_percent;
        pixels[pixel * 4 + 1] *= alpha_percent;
        pixels[pixel * 4 + 2] *= alpha_percent;
    }
 
    // return the modified frame
    return frame;
}
 
// Generate JSON string of this object
std::string Hue::Json() const {
 
    // Return formatted string
    return JsonValue().toStyledString();
}
 
// Generate Json::Value for this object
Json::Value Hue::JsonValue() const {
 
    // Create root json object
    Json::Value root = EffectBase::JsonValue(); // get parent properties
    root["type"] = info.class_name;
    root["hue"] = hue.JsonValue();
 
    // return JsonValue
    return root;
}
 
// Load JSON string into this object
void Hue::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 Hue::SetJsonValue(const Json::Value root) {
 
    // Set parent data
    EffectBase::SetJsonValue(root);
 
    // Set data from Json (if key is found)
    if (!root["hue"].isNull())
        hue.SetJsonValue(root["hue"]);
}
 
// Get all properties for a specific frame
std::string Hue::PropertiesJSON(int64_t requested_frame) const {
 
    // Generate JSON properties list
    Json::Value root = BasePropertiesJSON(requested_frame);
 
    // Keyframes
    root["hue"] = add_property_json("Hue", hue.GetValue(requested_frame), "float", "", &hue, 0.0, 1.0, false, requested_frame);
 
    // Return formatted string
    return root.toStyledString();
}