libopenshot/src/effects/Mask.cpp

/**
 * @file
 * @brief Source file for Mask class
 * @author Jonathan Thomas <jonathan@openshot.org>
 *
 * @ref License
 */

// 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"

#ifdef USE_IMAGEMAGICK
	#include "ImageReader.h"
#endif

using namespace openshot;

/// Blank constructor, useful when using Json to load the effect properties
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()
{
	/// Initialize the values of the EffectInfo struct.
	InitEffectInfo();

	/// Set the effect info
	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));
		}
	}

	// Refresh no longer needed
	needs_refresh = false;

	// Get pixel arrays
	unsigned char *pixels = (unsigned char *) frame_image->bits();
	unsigned char *mask_pixels = (unsigned char *) original_mask->bits();

	double contrast_value = (contrast.GetValue(frame_number));
	double brightness_value = (brightness.GetValue(frame_number));

	// Loop through mask pixels, and apply average gray value to frame alpha channel
	for (int pixel = 0, byte_index=0; pixel < original_mask->width() * original_mask->height(); pixel++, byte_index+=4)
	{
		// Get the RGB values from the pixel
		int R = mask_pixels[byte_index];
		int G = mask_pixels[byte_index + 1];
		int B = mask_pixels[byte_index + 2];
		int A = mask_pixels[byte_index + 3];

		// Get the average luminosity
		int gray_value = qGray(R, G, B);

		// Adjust the brightness
		gray_value += (255 * brightness_value);

		// Adjust the contrast
		float factor = (20 / std::fmax(0.00001, 20.0 - contrast_value));
		gray_value = (factor * (gray_value - 128) + 128);

		// Calculate the % change in alpha
		float alpha_percent = float(constrain(A - gray_value)) / 255.0;

		// Set the alpha channel to the gray value
		if (replace_image) {
			// Replace frame pixels with gray value (including alpha channel)
			pixels[byte_index + 0] = constrain(255 * alpha_percent);
			pixels[byte_index + 1] = constrain(255 * alpha_percent);
			pixels[byte_index + 2] = constrain(255 * alpha_percent);
			pixels[byte_index + 3] = constrain(255 * alpha_percent);
		} else {
			// Multiply new alpha value with all the colors (since we are using a premultiplied
			// alpha format)
			pixels[byte_index + 0] *= alpha_percent;
			pixels[byte_index + 1] *= alpha_percent;
			pixels[byte_index + 2] *= alpha_percent;
			pixels[byte_index + 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));

	// Add replace_image choices (dropdown style)
	root["apply_before_clip"]["choices"].append(add_property_choice_json("Yes", true, info.apply_before_clip));
	root["apply_before_clip"]["choices"].append(add_property_choice_json("No", false, info.apply_before_clip));

	// 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);

	// Set the parent effect which properties this effect will inherit
	root["parent_effect_id"] = add_property_json("Parent", 0.0, "string", info.parent_effect_id, NULL, -1, -1, false, requested_frame);

	// Return formatted string
	return root.toStyledString();
}