for viewer zooming, scale texture instead of surface #332

ui/viewercontainer.cpp

@@ -4,6 +4,7 @@
 #include <QResizeEvent>
 #include <QScrollBar>
 #include <QVBoxLayout>
+#include <QApplication>
 
 #include "viewerwidget.h"
 #include "panels/viewer.h"
@@ -12,42 +13,52 @@
 
 // enforces aspect ratio
 ViewerContainer::ViewerContainer(QWidget *parent) :
-	QScrollArea(parent),
+	QWidget(parent),
 	fit(true),
 	child(nullptr)
 {
-	setFrameShadow(QFrame::Plain);
-	setFrameShape(QFrame::NoFrame);
+	horizontal_scrollbar = new QScrollBar(Qt::Horizontal, this);
+	vertical_scrollbar = new QScrollBar(Qt::Vertical, this);
 
-	area = new QWidget(this);
-	area->move(0, 0);
-	setWidget(area);
+	horizontal_scrollbar->setSingleStep(20);
+	vertical_scrollbar->setSingleStep(20);
 
-	child = new ViewerWidget(area);
+	child = new ViewerWidget(this);
 	child->container = this;
+
+	connect(horizontal_scrollbar, SIGNAL(valueChanged(int)), this, SLOT(scroll_changed()));
+	connect(vertical_scrollbar, SIGNAL(valueChanged(int)), this, SLOT(scroll_changed()));
 }
 
 ViewerContainer::~ViewerContainer() {
 	delete child;
-	delete area;
+
+	delete horizontal_scrollbar;
+	delete vertical_scrollbar;
 }
 
 void ViewerContainer::dragScrollPress(const QPoint &p) {
 	drag_start_x = p.x();
 	drag_start_y = p.y();
-	horiz_start = horizontalScrollBar()->value();
-	vert_start = verticalScrollBar()->value();
+
+	horiz_start = horizontal_scrollbar->value();
+	vert_start = vertical_scrollbar->value();
 }
 
 void ViewerContainer::dragScrollMove(const QPoint &p) {
-	int true_x = p.x() + (horiz_start - horizontalScrollBar()->value());
-	int true_y = p.y() + (vert_start - verticalScrollBar()->value());
+	int this_x = p.x();
+	int this_y = p.y();
 
-	horizontalScrollBar()->setValue(horizontalScrollBar()->value() + (drag_start_x - true_x));
-	verticalScrollBar()->setValue(verticalScrollBar()->value() + (drag_start_y - true_y));
+	horizontal_scrollbar->setValue(horiz_start + (drag_start_x-this_x));
+	vertical_scrollbar->setValue(vert_start + (drag_start_y-this_y));
+}
 
-	drag_start_x = true_x;
-	drag_start_y = true_y;
+void ViewerContainer::parseWheelEvent(QWheelEvent *event) {
+	if (event->modifiers() & Qt::AltModifier) {
+		QApplication::sendEvent(horizontal_scrollbar, event);
+	} else {
+		QApplication::sendEvent(vertical_scrollbar, event);
+	}
 }
 
 void ViewerContainer::adjust() {
@@ -55,46 +66,87 @@ void ViewerContainer::adjust() {
 		if (child->waveform) {
 			child->move(0, 0);
 			child->resize(size());
-		} else if (fit) {
-			double aspect_ratio = double(viewer->seq->width)/double(viewer->seq->height);
-
-			int widget_x = 0;
-			int widget_y = 0;
-			int widget_width = width();
-			int widget_height = height();
-			double widget_ar = double(widget_width) / double(widget_height);
-
-			bool widget_is_wider_than_sequence = widget_ar > aspect_ratio;
-
-			if (widget_is_wider_than_sequence) {
-				widget_width = widget_height * aspect_ratio;
-				widget_x = (width() / 2) - (widget_width / 2);
-			} else {
-				widget_height = widget_width / aspect_ratio;
-				widget_y = (height() / 2) - (widget_height / 2);
-			}
-
-			child->move(widget_x, widget_y);
-			child->resize(widget_width, widget_height);
-
-			zoom = double(widget_width) / double(viewer->seq->width);
 		} else {
-			int zoomed_width = double(viewer->seq->width)*zoom;
-			int zoomed_height = double(viewer->seq->height)*zoom;
-			int zoomed_x = 0;
-			int zoomed_y = 0;
+			horizontal_scrollbar->setVisible(false);
+			vertical_scrollbar->setVisible(false);
 
-			if (zoomed_width < width()) zoomed_x = (width()>>1)-(zoomed_width>>1);
-			if (zoomed_height < height()) zoomed_y = (height()>>1)-(zoomed_height>>1);
+			int zoomed_width = qRound(double(viewer->seq->width)*zoom);
+			int zoomed_height = qRound(double(viewer->seq->height)*zoom);
 
-			child->move(zoomed_x, zoomed_y);
-			child->resize(zoomed_width, zoomed_height);
+			if (fit || zoomed_width > width() || zoomed_height > height()) {
+				// if the zoom size is greater than or equal to the available area, only use the available area
+
+				double aspect_ratio = double(viewer->seq->width)/double(viewer->seq->height);
+
+				int widget_x = 0;
+				int widget_y = 0;
+				int widget_width = width();
+				int widget_height = height();
+
+				if (!fit) {
+					widget_width -= vertical_scrollbar->width();
+					widget_height -= horizontal_scrollbar->height();
+				}
+
+				double widget_ar = double(widget_width) / double(widget_height);
+
+				bool widget_is_wider_than_sequence = widget_ar > aspect_ratio;
+
+				if (widget_is_wider_than_sequence) {
+					widget_width = widget_height * aspect_ratio;
+					widget_x = (width() / 2) - (widget_width / 2);
+				} else {
+					widget_height = widget_width / aspect_ratio;
+					widget_y = (height() / 2) - (widget_height / 2);
+				}
+
+				child->move(widget_x, widget_y);
+				child->resize(widget_width, widget_height);
+
+				if (fit) {
+					zoom = double(widget_width) / double(viewer->seq->width);
+				} else if (zoomed_width > width() || zoomed_height > height()) {
+					horizontal_scrollbar->setVisible(true);
+					vertical_scrollbar->setVisible(true);
+
+					horizontal_scrollbar->setMaximum(zoomed_width - width());
+					vertical_scrollbar->setMaximum(zoomed_height - height());
+
+					horizontal_scrollbar->setValue(horizontal_scrollbar->maximum()/2);
+					vertical_scrollbar->setValue(vertical_scrollbar->maximum()/2);
+				}
+			} else {
+				// if the zoom size is smaller than the available area, scale the surface down
+
+				int zoomed_x = 0;
+				int zoomed_y = 0;
+
+				if (zoomed_width < width()) zoomed_x = (width()>>1)-(zoomed_width>>1);
+				if (zoomed_height < height()) zoomed_y = (height()>>1)-(zoomed_height>>1);
+
+				child->move(zoomed_x, zoomed_y);
+				child->resize(zoomed_width, zoomed_height);
+			}
 		}
 	}
-	area->resize(qMax(width(), child->width()), qMax(height(), child->height()));
 }
 
 void ViewerContainer::resizeEvent(QResizeEvent *event) {
+	horizontal_scrollbar->move(0, height()-horizontal_scrollbar->height());
+	horizontal_scrollbar->setFixedWidth(width()-vertical_scrollbar->width());
+	horizontal_scrollbar->setPageStep(width());
+
+	vertical_scrollbar->move(width() - vertical_scrollbar->width(), 0);
+	vertical_scrollbar->setFixedHeight(height()-horizontal_scrollbar->height());
+	vertical_scrollbar->setPageStep(height());
+
 	event->accept();
 	adjust();
 }
+
+void ViewerContainer::scroll_changed() {
+	child->set_scroll(
+				double(horizontal_scrollbar->value())/double(horizontal_scrollbar->maximum()),
+				double(vertical_scrollbar->value())/double(vertical_scrollbar->maximum())
+			);
+}