/*
Copyright (C) 2012, University of Cambridge, Department of Psychiatry.
Created by Rudolf Cardinal (rnc1001@cam.ac.uk).
This file is part of CamCOPS.
CamCOPS is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
CamCOPS 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with CamCOPS. If not, see <https://www.gnu.org/licenses/>.
*/
/*
OPTIONAL LGPL: Alternatively, this file may be used under the terms of the
GNU Lesser General Public License version 3 as published by the Free
Software Foundation. You should have received a copy of the GNU Lesser
General Public License along with CamCOPS. If not, see
<https://www.gnu.org/licenses/>.
*/
#pragma once
// http://stackoverflow.com/questions/5653114/display-image-in-qt-to-fit-label-size
// http://stackoverflow.com/questions/8211982/qt-resizing-a-qlabel-containing-a-qpixmap-while-keeping-its-aspect-ratio
// ... hacked around a bit, because it wasn't using more size when offered
// http://stackoverflow.com/questions/24264320/qt-layouts-keep-widget-aspect-ratio-while-resizing/24264774
// Eventually this:
// http://stackoverflow.com/questions/452333/how-to-maintain-widgets-aspect-ratio-in-qt
// https://forum.qt.io/topic/29859/solved-trying-to-fix-aspect-ratio-of-a-widget-big-problems-with-layouts/5
// Consensus that setHeightForWidth doesn't work terribly well...
#include <QLabel>
#include <QWidget>
class QMouseEvent;
class QResizeEvent;
class AspectRatioPixmap : public QWidget
{
// Image that retains its aspect ratio, for displaying photos.
//
// - Displays image UP TO its original size.
//
// - Clickable, in a simple way (as per
// https://wiki.qt.io/Clickable_QLabel).
//
// - this form of clicking responds immediately, not as you release the
// mouse click (cf. QAbstractButton); however, there is no visual
// display that responds to the start of the click, so maybe that is
// reasonable.
// - For another way of responding to clicks, see ClickableLabel.
// For speed, DO NOT allow resizeEvent() to call some sort of function like
// QLabel::setPixmap(scaledPixmap()). That leads to terminal slowness with
// large images.
// Instead, store a size, and plot the image to that size as required.
// Compare CanvasWidget, which also does that.
Q_OBJECT
public:
// Constructor. Sets image.
explicit AspectRatioPixmap(QPixmap* pixmap = nullptr,
QWidget* parent = nullptr);
// Standard Qt widget overrides.
virtual bool hasHeightForWidth() const override;
virtual int heightForWidth(int width) const override;
virtual QSize sizeHint() const override;
virtual QSize minimumSizeHint() const override;
// Removes the image.
void clear();
protected:
// Standard Qt widget overrides.
virtual void mousePressEvent(QMouseEvent* event) override;
virtual void paintEvent(QPaintEvent* event) override;
signals:
// "Image was clicked."
void clicked();
public slots:
// Sets a new image.
virtual void setPixmap(const QPixmap& pixmap); // WON'T OVERRIDE.
private:
QPixmap m_pixmap; // our image
};