libopenshot/src/effects/Brightness.cpp

/**
 * @file
 * @brief Source file for Brightness class
 * @author Jonathan Thomas <jonathan@openshot.org>
 *
 * @section LICENSE
 *
 * Copyright (c) 2008-2014 OpenShot Studios, LLC
 * <http://www.openshotstudios.com/>. This file is part of
 * OpenShot Library (libopenshot), an open-source project dedicated to
 * delivering high quality video editing and animation solutions to the
 * world. For more information visit <http://www.openshot.org/>.
 *
 * OpenShot Library (libopenshot) is free software: you can redistribute it
 * and/or modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * OpenShot Library (libopenshot) is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with OpenShot Library. If not, see <http://www.gnu.org/licenses/>.
 */

#include "../../include/effects/Brightness.h"

using namespace openshot;

/// Blank constructor, useful when using Json to load the effect properties
Brightness::Brightness() : brightness(0.0), contrast(3.0) {
	// Init effect properties
	init_effect_details();
}

// Default constructor
Brightness::Brightness(Keyframe new_brightness, Keyframe new_contrast) : brightness(new_brightness), contrast(new_contrast)
{
	// Init effect properties
	init_effect_details();
}

// Init effect settings
void Brightness::init_effect_details()
{
	/// Initialize the values of the EffectInfo struct.
	InitEffectInfo();

	/// Set the effect info
	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;
}

// Constrain a color value from 0 to 255
int Brightness::constrain(int color_value)
{
	// Constrain new color from 0 to 255
	if (color_value < 0)
		color_value = 0;
	else if (color_value > 255)
		color_value = 255;

	return color_value;
}


// This method is required for all derived classes of EffectBase, and returns a
// modified openshot::Frame object
std::shared_ptr<Frame> Brightness::GetFrame(std::shared_ptr<Frame> frame, long int frame_number)
{
	// Get the frame's image
	std::shared_ptr<QImage> frame_image = frame->GetImage();

	// Get keyframe values for this frame
	float brightness_value = brightness.GetValue(frame_number);
	float contrast_value = contrast.GetValue(frame_number);

	// Loop through pixels
	unsigned char *pixels = (unsigned char *) frame_image->bits();
	for (int pixel = 0, byte_index=0; pixel < frame_image->width() * frame_image->height(); pixel++, byte_index+=4)
	{
		// Get the RGB values from the pixel
		int R = pixels[byte_index];
		int G = pixels[byte_index + 1];
		int B = pixels[byte_index + 2];
		int A = pixels[byte_index + 3];

		// Adjust the contrast
		int factor = (259 * (contrast_value + 255)) / (255 * (259 - contrast_value));
		R = constrain((factor * (R - 128)) + 128);
		G = constrain((factor * (G - 128)) + 128);
		B = constrain((factor * (B - 128)) + 128);

		// Adjust the brightness
		R += (255 * brightness_value);
		G += (255 * brightness_value);
		B += (255 * brightness_value);

		// Constrain the value from 0 to 255
		R = constrain(R);
		G = constrain(G);
		B = constrain(B);

		// Set all pixels to new value
		pixels[byte_index] = R;
		pixels[byte_index + 1] = G;
		pixels[byte_index + 2] = B;
		pixels[byte_index + 3] = A; // leave the alpha value alone
	}

	// return the modified frame
	return frame;
}

// Generate JSON string of this object
string Brightness::Json() {

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

// Generate Json::JsonValue for this object
Json::Value Brightness::JsonValue() {

	// 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();

	// return JsonValue
	return root;
}

// Load JSON string into this object
void Brightness::SetJson(string value) throw(InvalidJSON) {

	// Parse JSON string into JSON objects
	Json::Value root;
	Json::Reader reader;
	bool success = reader.parse( value, root );
	if (!success)
		// Raise exception
		throw InvalidJSON("JSON could not be parsed (or is invalid)", "");

	try
	{
		// Set all values that match
		SetJsonValue(root);
	}
	catch (exception e)
	{
		// Error parsing JSON (or missing keys)
		throw InvalidJSON("JSON is invalid (missing keys or invalid data types)", "");
	}
}

// Load Json::JsonValue into this object
void Brightness::SetJsonValue(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"]);
}

// Get all properties for a specific frame
string Brightness::PropertiesJSON(long int requested_frame) {

	// Generate JSON properties list
	Json::Value root;
	root["id"] = add_property_json("ID", 0.0, "string", Id(), NULL, -1, -1, true, requested_frame);
	root["position"] = add_property_json("Position", Position(), "float", "", NULL, 0, 30 * 60 * 60 * 48, false, requested_frame);
	root["layer"] = add_property_json("Track", Layer(), "int", "", NULL, 0, 20, false, requested_frame);
	root["start"] = add_property_json("Start", Start(), "float", "", NULL, 0, 30 * 60 * 60 * 48, false, requested_frame);
	root["end"] = add_property_json("End", End(), "float", "", NULL, 0, 30 * 60 * 60 * 48, false, requested_frame);
	root["duration"] = add_property_json("Duration", Duration(), "float", "", NULL, 0, 30 * 60 * 60 * 48, true, 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, 0.0, 100.0, false, requested_frame);

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