profile: remove need for MainWindow when rendering the profile

Very annoyingly, to render the profile for printing / export,
the profile still had to be show()n, thus requiring a parent
window.

Analysis of qmlprofile.c showed that this was due to the
transformation matrix not being properly set up on non-show()n
scenes.

Instead, we can simply render via the QGraphicsScene
(circumventing the QGraphicsView).

The code was factored out into the ProfileWidget2::draw()
function. This will hopefully make it easier to change
the size-code of the profile.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

backend-shared/exportfuncs.cpp

@@ -34,32 +34,27 @@ bool ExportCallback::canceled() const
 
 #if !defined(SUBSURFACE_MOBILE)
 
-#include "desktop-widgets/mainwindow.h" // Currently needed for profile printing. TODO: remove.
+// Let's say that 800x600 is a "reasonable" profile size. Use four times that for printing.
+static constexpr int profileScale = 4;
+static constexpr int profileWidth = 800 * profileScale;
+static constexpr int profileHeight = 600 * profileScale;
 
 static void exportProfile(ProfileWidget2 *profile, const struct dive *dive, const QString &filename)
 {
 	profile->setProfileState(dive, 0);
 	profile->plotDive(dive, 0, false, true);
-	QImage image = QImage(profile->size(), QImage::Format_RGB32);
+	QImage image = QImage(QSize(profileWidth, profileHeight), QImage::Format_RGB32);
 	QPainter paint;
 	paint.begin(&image);
-	profile->render(&paint);
+	profile->draw(&paint, QRect(0, 0, profileWidth, profileHeight));
 	image.save(filename);
 }
 
 static std::unique_ptr<ProfileWidget2> getPrintProfile()
 {
-	// Let's say that 800x600 is a "reasonable" profile size. Use four times that for printing.
-	const int scale = 4;
-	QSize size(800 * scale, 600 * scale);
-
-	// TODO: Annoyingly, this still needs a parent window? Otherwise,
-	// the profile is shown as its own window, when calling show() below.
-	auto profile = std::make_unique<ProfileWidget2>(nullptr, MainWindow::instance());
-	profile->resize(size);
-	profile->show();	// Ominous: if the scene isn't shown, parts of the plot are missing. Needs investigation.
+	auto profile = std::make_unique<ProfileWidget2>(nullptr, nullptr);
 	profile->setPrintMode(true);
-	profile->setFontPrintScale((double)scale);
+	profile->setFontPrintScale((double)profileScale);
 	return profile;
 }
 

desktop-widgets/diveplanner.cpp

@@ -609,15 +609,11 @@ void PlannerWidgets::printDecoPlan()
 	painter.setRenderHint(QPainter::Antialiasing);
 	painter.setRenderHint(QPainter::SmoothPixmapTransform);
 
-	// TODO: Annoyingly, this still needs a parent window? Otherwise,
-	// the profile is shown as its own window, when calling show() below.
-	auto profile = std::make_unique<ProfileWidget2>(DivePlannerPointsModel::instance(), MainWindow::instance());
-	profile->show();	// Ominous: if the scene isn't shown, parts of the plot are missing. Needs investigation.
-	profile->resize(renderSize.toSize());
+	auto profile = std::make_unique<ProfileWidget2>(DivePlannerPointsModel::instance(), nullptr);
 	profile->setPlanState(&displayed_dive, 0);
 	profile->plotDive(&displayed_dive, 0, true, true);
 	profile->setPrintMode(true);
-	profile->render(&painter);
+	profile->draw(&painter, QRect(0, 0, pixmap.width(), pixmap.height()));
 
 	QByteArray byteArray;
 	QBuffer buffer(&byteArray);

desktop-widgets/printer.cpp

@@ -1,6 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
 #include "printer.h"
-#include "mainwindow.h"
 #include "templatelayout.h"
 #include "core/statistics.h"
 #include "core/qthelper.h"
@@ -36,31 +35,10 @@ void Printer::putProfileImage(const QRect &profilePlaceholder, const QRect &view
 	int y = profilePlaceholder.y() - viewPort.y();
 	// use the placeHolder and the viewPort position to calculate the relative position of the dive profile.
 	QRect pos(x, y, profilePlaceholder.width(), profilePlaceholder.height());
+
 	profile->setProfileState(dive, 0);
 	profile->plotDive(dive, 0, true);
-
-	if (!printOptions.color_selected) {
-		QImage image(pos.width(), pos.height(), QImage::Format_ARGB32);
-		QPainter imgPainter(&image);
-		imgPainter.setRenderHint(QPainter::Antialiasing);
-		imgPainter.setRenderHint(QPainter::SmoothPixmapTransform);
-		profile->render(&imgPainter, QRect(0, 0, pos.width(), pos.height()));
-		imgPainter.end();
-
-		// convert QImage to grayscale before rendering
-		for (int i = 0; i < image.height(); i++) {
-			QRgb *pixel = reinterpret_cast<QRgb *>(image.scanLine(i));
-			QRgb *end = pixel + image.width();
-			for (; pixel != end; pixel++) {
-				int gray_val = qGray(*pixel);
-				*pixel = QColor(gray_val, gray_val, gray_val).rgb();
-			}
-		}
-
-		painter->drawImage(pos, image);
-	} else {
-		profile->render(painter, pos);
-	}
+	profile->draw(painter, pos);
 }
 
 void Printer::flowRender()
@@ -124,9 +102,7 @@ void Printer::flowRender()
 
 void Printer::render(int pages)
 {
-	// TODO: Annoyingly, this still needs a parent window? Otherwise,
-	// the profile is shown as its own window, when calling show() below.
-	auto profile = std::make_unique<ProfileWidget2>(nullptr, MainWindow::instance());
+	auto profile = std::make_unique<ProfileWidget2>(nullptr, nullptr);
 	double printFontScale = 1.0;
 
 	// apply printing settings to profile
@@ -149,8 +125,6 @@ void Printer::render(int pages)
 		// This is arbitrary, but it seems to work reasonably.
 		QSize size = collection[0].geometry().size();
 		printFontScale = size.height() / 600.0;
-		profile->show();	// Ominous: if the scene isn't shown, parts of the plot are missing. Needs investigation.
-		profile->resize(size);
 	}
 	profile->setFontPrintScale(printFontScale);
 

profile-widget/profilewidget2.cpp

@@ -2161,3 +2161,39 @@ struct dive *ProfileWidget2::mutable_dive() const
 {
 	return const_cast<dive *>(d);
 }
+
+QImage ProfileWidget2::toImage(QSize size)
+{
+	// The size of chart with respect to the scene is fixed - by convention - to 100.0.
+	// We add 2% to the height so that the dive computer name is not cut off.
+	QRectF sceneRect(0.0, 0.0, 100.0, 102.0);
+
+	QImage image(size, QImage::Format_ARGB32);
+	image.fill(getColor(::BACKGROUND, isGrayscale));
+
+	QPainter imgPainter(&image);
+	imgPainter.setRenderHint(QPainter::Antialiasing);
+	imgPainter.setRenderHint(QPainter::SmoothPixmapTransform);
+	scene()->render(&imgPainter, QRect(QPoint(), size), sceneRect, Qt::IgnoreAspectRatio);
+	imgPainter.end();
+
+	if (isGrayscale) {
+		// convert QImage to grayscale before rendering
+		for (int i = 0; i < image.height(); i++) {
+			QRgb *pixel = reinterpret_cast<QRgb *>(image.scanLine(i));
+			QRgb *end = pixel + image.width();
+			for (; pixel != end; pixel++) {
+				int gray_val = qGray(*pixel);
+				*pixel = QColor(gray_val, gray_val, gray_val).rgb();
+			}
+		}
+	}
+
+	return image;
+}
+
+void ProfileWidget2::draw(QPainter *painter, const QRect &pos)
+{
+	QImage img = toImage(pos.size());
+	painter->drawImage(pos, img);
+}

profile-widget/profilewidget2.h

@@ -79,6 +79,8 @@ public:
 	bool isPlanner() const;
 	double getFontPrintScale() const;
 	void setFontPrintScale(double scale);
+	void draw(QPainter *painter, const QRect &pos);
+	QImage toImage(QSize size);
 #ifndef SUBSURFACE_MOBILE
 	bool eventFilter(QObject *, QEvent *) override;
 #endif