libopenshot/src/effects/Caption.cpp

/**
 * @file
 * @brief Source file for Caption effect 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 "Caption.h"
#include "Exceptions.h"
#include "../Clip.h"
#include "../Timeline.h"

#include <QString>
#include <QPoint>
#include <QRect>
#include <QPen>
#include <QBrush>
#include <QPainter>
#include <QPainterPath>

using namespace openshot;

/// Blank constructor, useful when using Json to load the effect properties
Caption::Caption() : color("#ffffff"), stroke("#a9a9a9"), background("#ff000000"), background_alpha(0.0), left(0.15), top(0.7), right(0.15),
					 stroke_width(0.5), font_size(30.0), font_alpha(1.0), is_dirty(true), font_name("sans"), font(NULL), metrics(NULL),
					 fade_in(0.35), fade_out(0.35), background_corner(10.0), background_padding(20.0), line_spacing(1.0)
{
	// Init effect properties
	init_effect_details();
}

// Default constructor
Caption::Caption(std::string captions) :
		color("#ffffff"), caption_text(captions), stroke("#a9a9a9"), background("#ff000000"), background_alpha(0.0),
		left(0.15), top(0.7), right(0.15), stroke_width(0.5), font_size(30.0), font_alpha(1.0), is_dirty(true), font_name("sans"),
		font(NULL), metrics(NULL), fade_in(0.35), fade_out(0.35), background_corner(10.0), background_padding(20.0), line_spacing(1.0)
{
	// Init effect properties
	init_effect_details();
}

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

	/// Set the effect info
	info.class_name = "Caption";
	info.name = "Caption";
	info.description = "Add text captions on top of your video.";
	info.has_audio = false;
	info.has_video = true;

	// Init placeholder caption (for demo)
	if (caption_text.length() == 0) {
		caption_text = "00:00:00:000 --> 00:10:00:000\nEdit this caption with our caption editor";
	}
}

// Set the caption string to use (see VTT format)
std::string Caption::CaptionText() {
	return caption_text;
}

// Get the caption string
void Caption::CaptionText(std::string new_caption_text) {
	caption_text = new_caption_text;
	is_dirty = true;
}

// Process regex string only when dirty
void Caption::process_regex() {
	if (is_dirty) {
		is_dirty = false;

		// Clear existing matches
		matchedCaptions.clear();

		QString caption_prepared = QString(caption_text.c_str());
		if (caption_prepared.endsWith("\n\n") == false) {
			// We need a couple line ends at the end of the caption string (for our regex to work correctly)
			caption_prepared.append("\n\n");
		}

		// Parse regex and find all matches
		QRegularExpression allPathsRegex(QStringLiteral("(\\d{2})?:*(\\d{2}):(\\d{2}).(\\d{2,3})\\s*-->\\s*(\\d{2})?:*(\\d{2}):(\\d{2}).(\\d{2,3})([\\s\\S]*?)\\n(.*?)(?=\\n\\d{2,3}|\\Z)"), QRegularExpression::MultilineOption);
		QRegularExpressionMatchIterator i = allPathsRegex.globalMatch(caption_prepared);
		while (i.hasNext()) {
			QRegularExpressionMatch match = i.next();
			if (match.hasMatch()) {
				// Push all match objects into a vector (so we can reverse them later)
				matchedCaptions.push_back(match);
			}
		}
	}
}

// This method is required for all derived classes of EffectBase, and returns a
// modified openshot::Frame object
std::shared_ptr<openshot::Frame> Caption::GetFrame(std::shared_ptr<openshot::Frame> frame, int64_t frame_number)
{
	// Process regex (if needed)
	process_regex();

	// Get the Clip and Timeline pointers (if available)
	Clip* clip = (Clip*) ParentClip();
	Timeline* timeline = NULL;
	Fraction fps;
	double scale_factor = 1.0; // amount of scaling needed for text (based on preview window size)
	if (clip && clip->ParentTimeline() != NULL) {
		timeline = (Timeline*) clip->ParentTimeline();
	} else if (this->ParentTimeline() != NULL) {
		timeline = (Timeline*) this->ParentTimeline();
	}

	// Get the FPS from the parent object (Timeline or Clip's Reader)
	if (timeline != NULL) {
		fps.num = timeline->info.fps.num;
		fps.den = timeline->info.fps.den;
		// preview window is sometimes smaller/larger than the timeline size
		scale_factor = (double) timeline->preview_width / (double) timeline->info.width;
	} else if (clip != NULL && clip->Reader() != NULL) {
		fps.num = clip->Reader()->info.fps.num;
		fps.den = clip->Reader()->info.fps.den;
		scale_factor = 1.0;
	}

	// Get the frame's image
	std::shared_ptr<QImage> frame_image = frame->GetImage();

	// Load timeline's new frame image into a QPainter
	QPainter painter(frame_image.get());
	painter.setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform | QPainter::TextAntialiasing, true);

	// Composite a new layer onto the image
	painter.setCompositionMode(QPainter::CompositionMode_SourceOver);

	// Font options and metrics for caption text
	double font_size_value = font_size.GetValue(frame_number) * scale_factor;
	QFont font(QString(font_name.c_str()), int(font_size_value));
	font.setPointSizeF(std::max(font_size_value, 1.0));
	QFontMetricsF metrics = QFontMetricsF(font);

	// Get current keyframe values
	double left_value = left.GetValue(frame_number);
	double top_value = top.GetValue(frame_number);
	double fade_in_value = fade_in.GetValue(frame_number) * fps.ToDouble();
	double fade_out_value = fade_out.GetValue(frame_number) * fps.ToDouble();
	double right_value = right.GetValue(frame_number);
	double background_corner_value = background_corner.GetValue(frame_number) * scale_factor;
	double padding_value = background_padding.GetValue(frame_number) * scale_factor;
	double stroke_width_value = stroke_width.GetValue(frame_number) * scale_factor;
	double line_spacing_value = line_spacing.GetValue(frame_number);
	double metrics_line_spacing = metrics.lineSpacing();

	// Calculate caption area (based on left, top, and right margin)
	double left_margin_x = frame_image->width() * left_value;
	double starting_y = (frame_image->height() * top_value) + metrics_line_spacing;
	double current_y = starting_y;
	double bottom_y = starting_y;
	double top_y = starting_y;
	double max_text_width = 0.0;
	double right_margin_x = frame_image->width() - (frame_image->width() * right_value);
	double caption_area_width = right_margin_x - left_margin_x;
	QRectF caption_area = QRectF(left_margin_x, starting_y, caption_area_width, frame_image->height());

	// Keep track of all required text paths
	std::vector<QPainterPath> text_paths;
	double fade_in_percentage = 0.0;
	double fade_out_percentage = 0.0;
	double line_height = metrics_line_spacing * line_spacing_value;

	// Loop through matches and find text to display (if any)
	for (auto match = matchedCaptions.begin(); match != matchedCaptions.end(); match++) {

		// Build timestamp (00:00:04.000 --> 00:00:06.500)
		int64_t start_frame = ((match->captured(1).toFloat() * 60.0 * 60.0 ) + (match->captured(2).toFloat() * 60.0 ) +
							   match->captured(3).toFloat() + (match->captured(4).toFloat() / 1000.0)) * fps.ToFloat();
		int64_t end_frame = ((match->captured(5).toFloat() * 60.0 * 60.0 ) + (match->captured(6).toFloat() * 60.0 ) +
							 match->captured(7).toFloat() + (match->captured(8).toFloat() / 1000.0)) * fps.ToFloat();

		// Split multiple lines into separate paths
		QStringList lines = match->captured(9).split("\n");
		for(int index = 0; index < lines.length(); index++) {
			// Multi-line
			QString line = lines[index];
			// Ignore lines that start with NOTE, or are <= 1 char long
			if (!line.startsWith(QStringLiteral("NOTE")) &&
				!line.isEmpty() && frame_number >= start_frame && frame_number <= end_frame && line.length() > 1) {

				// Calculate fade in/out ranges
				fade_in_percentage = ((float) frame_number - (float) start_frame) / fade_in_value;
				fade_out_percentage = 1.0 - (((float) frame_number - ((float) end_frame - fade_out_value)) / fade_out_value);

				// Loop through words, and find word-wrap boundaries
				QStringList words = line.split(" ");
				int words_remaining = words.length();
				while (words_remaining > 0) {
					bool words_displayed = false;
					for(int word_index = words.length(); word_index > 0; word_index--) {
						// Current matched caption string (from the beginning to the current word index)
						QString fitting_line = words.mid(0, word_index).join(" ");

						// Calculate size of text
						QRectF textRect = metrics.boundingRect(caption_area, Qt::TextSingleLine, fitting_line);
						if (textRect.width() <= caption_area.width()) {
							// Location for text
							QPoint p(left_margin_x, current_y);

							// Create path and add text to it (for correct border and fill)
							QPainterPath path1;
							QString fitting_line = words.mid(0, word_index).join(" ");
							path1.addText(p, font, fitting_line);
							text_paths.push_back(path1);

							// Update line (to remove words already drawn
							words = words.mid(word_index, words.length());
							words_remaining = words.length();
							words_displayed = true;

							// Increment y-coordinate of text (for next line) + padding
							current_y += line_height;

							// Detect max width (of widest text line)
							if (path1.boundingRect().width() > max_text_width) {
								max_text_width = path1.boundingRect().width();
							}
							// Detect top most y coordinate of text
							if (path1.boundingRect().top() < top_y) {
								top_y = path1.boundingRect().top();
							}
							// Detect bottom most y coordinate of text
							if (path1.boundingRect().bottom() > bottom_y) {
								bottom_y = path1.boundingRect().bottom();
							}
							break;
						}
					}

					if (!words_displayed) {
						// Exit loop if no words displayed
						words_remaining = 0;
					}
				}

			}
		}
	}

	// Calculate background size w/padding (based on actual text-wrapping)
	QRectF caption_area_with_padding = QRectF(left_margin_x - (padding_value / 2.0),
											  top_y - (padding_value / 2.0),
											  max_text_width + padding_value,
											  (bottom_y - top_y) + padding_value);

	// Calculate alignment offset on X axis (force center alignment of the caption area)
	double alignment_offset = std::max((caption_area_width - max_text_width) / 2.0, 0.0);

	// Set background color of caption
	QBrush background_brush;
	QColor background_qcolor = QColor(QString(background.GetColorHex(frame_number).c_str()));
	// Align background center
	caption_area_with_padding.translate(alignment_offset, 0.0);
	if (fade_in_percentage < 1.0) {
		// Fade in background
		background_qcolor.setAlphaF(fade_in_percentage * background_alpha.GetValue(frame_number));
	} else if (fade_out_percentage >= 0.0 && fade_out_percentage <= 1.0) {
		// Fade out background
		background_qcolor.setAlphaF(fade_out_percentage * background_alpha.GetValue(frame_number));
	} else {
		background_qcolor.setAlphaF(background_alpha.GetValue(frame_number));
	}
	background_brush.setColor(background_qcolor);
	background_brush.setStyle(Qt::SolidPattern);
	painter.setBrush(background_brush);
	painter.setPen(Qt::NoPen);
	painter.drawRoundedRect(caption_area_with_padding, background_corner_value, background_corner_value);

	// Set fill-color of text
	QBrush font_brush;
	QColor font_qcolor = QColor(QString(color.GetColorHex(frame_number).c_str()));
	font_qcolor.setAlphaF(font_alpha.GetValue(frame_number));
	font_brush.setStyle(Qt::SolidPattern);

	// Set stroke/border color of text
	QPen pen;
	QColor stroke_qcolor;
	stroke_qcolor = QColor(QString(stroke.GetColorHex(frame_number).c_str()));
	stroke_qcolor.setAlphaF(font_alpha.GetValue(frame_number));
	pen.setColor(stroke_qcolor);
	pen.setWidthF(std::max(stroke_width_value, 0.0));
	painter.setPen(pen);

	// Loop through text paths
	for(QPainterPath path : text_paths) {
		// Align text center (relative to background)
		path.translate(alignment_offset, 0.0);
		if (fade_in_percentage < 1.0) {
			// Fade in text
			font_qcolor.setAlphaF(fade_in_percentage * font_alpha.GetValue(frame_number));
			stroke_qcolor.setAlphaF(fade_in_percentage * font_alpha.GetValue(frame_number));
		} else if (fade_out_percentage >= 0.0 && fade_out_percentage <= 1.0) {
			// Fade out text
			font_qcolor.setAlphaF(fade_out_percentage * font_alpha.GetValue(frame_number));
			stroke_qcolor.setAlphaF(fade_out_percentage * font_alpha.GetValue(frame_number));
		}
		pen.setColor(stroke_qcolor);
		font_brush.setColor(font_qcolor);

		// Set stroke pen
		if (stroke_width_value <= 0.0) {
			painter.setPen(Qt::NoPen);
		} else {
			painter.setPen(pen);
		}

		painter.setBrush(font_brush);
		painter.drawPath(path);
	}

	// End painter
	painter.end();

	// return the modified frame
	return frame;
}

// Generate JSON string of this object
std::string Caption::Json() const {

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

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

	// Create root json object
	Json::Value root = EffectBase::JsonValue(); // get parent properties
	root["type"] = info.class_name;
	root["color"] = color.JsonValue();
	root["stroke"] = stroke.JsonValue();
	root["background"] = background.JsonValue();
	root["background_alpha"] = background_alpha.JsonValue();
	root["background_corner"] = background_corner.JsonValue();
	root["background_padding"] = background_padding.JsonValue();
	root["stroke_width"] = stroke_width.JsonValue();
	root["font_size"] = font_size.JsonValue();
	root["font_alpha"] = font_alpha.JsonValue();
	root["fade_in"] = fade_in.JsonValue();
	root["fade_out"] = fade_out.JsonValue();
	root["line_spacing"] = line_spacing.JsonValue();
	root["left"] = left.JsonValue();
	root["top"] = top.JsonValue();
	root["right"] = right.JsonValue();
	root["caption_text"] = caption_text;
	root["caption_font"] = font_name;

	// return JsonValue
	return root;
}

// Load JSON string into this object
void Caption::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 Caption::SetJsonValue(const Json::Value root) {

	// Set parent data
	EffectBase::SetJsonValue(root);

	// Set data from Json (if key is found)
	if (!root["color"].isNull())
		color.SetJsonValue(root["color"]);
	if (!root["stroke"].isNull())
		stroke.SetJsonValue(root["stroke"]);
	if (!root["background"].isNull())
		background.SetJsonValue(root["background"]);
	if (!root["background_alpha"].isNull())
		background_alpha.SetJsonValue(root["background_alpha"]);
	if (!root["background_corner"].isNull())
		background_corner.SetJsonValue(root["background_corner"]);
	if (!root["background_padding"].isNull())
		background_padding.SetJsonValue(root["background_padding"]);
	if (!root["stroke_width"].isNull())
		stroke_width.SetJsonValue(root["stroke_width"]);
	if (!root["font_size"].isNull())
		font_size.SetJsonValue(root["font_size"]);
	if (!root["font_alpha"].isNull())
		font_alpha.SetJsonValue(root["font_alpha"]);
	if (!root["fade_in"].isNull())
		fade_in.SetJsonValue(root["fade_in"]);
	if (!root["fade_out"].isNull())
		fade_out.SetJsonValue(root["fade_out"]);
	if (!root["line_spacing"].isNull())
		line_spacing.SetJsonValue(root["line_spacing"]);
	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["caption_text"].isNull())
		caption_text = root["caption_text"].asString();
	if (!root["caption_font"].isNull())
		font_name = root["caption_font"].asString();

	// Mark effect as dirty to reparse Regex
	is_dirty = true;
}

// Get all properties for a specific frame
std::string Caption::PropertiesJSON(int64_t requested_frame) const {

	// 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, 1000 * 60 * 30, 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, 1000 * 60 * 30, false, requested_frame);
	root["end"] = add_property_json("End", End(), "float", "", NULL, 0, 1000 * 60 * 30, false, requested_frame);
	root["duration"] = add_property_json("Duration", Duration(), "float", "", NULL, 0, 1000 * 60 * 30, true, requested_frame);

	// Keyframes
	root["color"] = add_property_json("Color", 0.0, "color", "", &color.red, 0, 255, false, requested_frame);
	root["color"]["red"] = add_property_json("Red", color.red.GetValue(requested_frame), "float", "", &color.red, 0, 255, false, requested_frame);
	root["color"]["blue"] = add_property_json("Blue", color.blue.GetValue(requested_frame), "float", "", &color.blue, 0, 255, false, requested_frame);
	root["color"]["green"] = add_property_json("Green", color.green.GetValue(requested_frame), "float", "", &color.green, 0, 255, false, requested_frame);
	root["stroke"] = add_property_json("Border", 0.0, "color", "", &stroke.red, 0, 255, false, requested_frame);
	root["stroke"]["red"] = add_property_json("Red", stroke.red.GetValue(requested_frame), "float", "", &stroke.red, 0, 255, false, requested_frame);
	root["stroke"]["blue"] = add_property_json("Blue", stroke.blue.GetValue(requested_frame), "float", "", &stroke.blue, 0, 255, false, requested_frame);
	root["stroke"]["green"] = add_property_json("Green", stroke.green.GetValue(requested_frame), "float", "", &stroke.green, 0, 255, false, requested_frame);
	root["background_alpha"] = add_property_json("Background Alpha", background_alpha.GetValue(requested_frame), "float", "", &background_alpha, 0.0, 1.0, false, requested_frame);
	root["background_corner"] = add_property_json("Background Corner Radius", background_corner.GetValue(requested_frame), "float", "", &background_corner, 0.0, 60.0, false, requested_frame);
	root["background_padding"] = add_property_json("Background Padding", background_padding.GetValue(requested_frame), "float", "", &background_padding, 0.0, 60.0, false, requested_frame);
	root["background"] = add_property_json("Background", 0.0, "color", "", &background.red, 0, 255, false, requested_frame);
	root["background"]["red"] = add_property_json("Red", background.red.GetValue(requested_frame), "float", "", &background.red, 0, 255, false, requested_frame);
	root["background"]["blue"] = add_property_json("Blue", background.blue.GetValue(requested_frame), "float", "", &background.blue, 0, 255, false, requested_frame);
	root["background"]["green"] = add_property_json("Green", background.green.GetValue(requested_frame), "float", "", &background.green, 0, 255, false, requested_frame);
	root["stroke_width"] = add_property_json("Stroke Width", stroke_width.GetValue(requested_frame), "float", "", &stroke_width, 0, 10.0, false, requested_frame);
	root["font_size"] = add_property_json("Font Size", font_size.GetValue(requested_frame), "float", "", &font_size, 0, 200.0, false, requested_frame);
	root["font_alpha"] = add_property_json("Font Alpha", font_alpha.GetValue(requested_frame), "float", "", &font_alpha, 0.0, 1.0, false, requested_frame);
	root["fade_in"] = add_property_json("Fade In (Seconds)", fade_in.GetValue(requested_frame), "float", "", &fade_in, 0.0, 3.0, false, requested_frame);
	root["fade_out"] = add_property_json("Fade Out (Seconds)", fade_out.GetValue(requested_frame), "float", "", &fade_out, 0.0, 3.0, false, requested_frame);
	root["line_spacing"] = add_property_json("Line Spacing", line_spacing.GetValue(requested_frame), "float", "", &line_spacing, 0.0, 5.0, false, requested_frame);
	root["left"] = add_property_json("Left Size", left.GetValue(requested_frame), "float", "", &left, 0.0, 0.5, false, requested_frame);
	root["top"] = add_property_json("Top Size", top.GetValue(requested_frame), "float", "", &top, 0.0, 1.0, false, requested_frame);
	root["right"] = add_property_json("Right Size", right.GetValue(requested_frame), "float", "", &right, 0.0, 0.5, false, requested_frame);
	root["caption_text"] = add_property_json("Captions", 0.0, "caption", caption_text, NULL, -1, -1, false, requested_frame);
	root["caption_font"] = add_property_json("Font", 0.0, "font", font_name, NULL, -1, -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();
}