Copyright (C) 2012-2020 Rudolf Cardinal (email@example.com).
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 <http://www.gnu.org/licenses/>.
class SvgWidgetClickable : public QSvgWidget
// Widget that displays an SVG graphics image, and is clickable.
// Used for response elements (e.g. in ID/ED-3D task).
// We have a choice of deriving from QGraphicsSvgItem or QSvgWidget.
// The main differences are:
// - QSvgWidget can be used in a more general context
// - QSvgWidget owns its QSvgRenderer, but you can access it, while if you
// use a QGraphicsSvgItem, you have to manage the lifetime of the
// renderer separately, which is something of a pain.
// For clicks:
// - https://stackoverflow.com/questions/36372615/how-can-i-capture-click-events-signals-of-a-qgraphicssvgitem
// For changing the background colour when pressed:
// - The ":pseudo" stylesheet selector doesn't work; possibly that's
// only for QAbstractButton.
// - You can't both override paintEvent() and call the base class
// - https://stackoverflow.com/questions/13897026/accessing-a-qpainter-in-base-class
// - http://doc.qt.io/qt-4.8/qpainter.html#begin
// - Aha! You can. You just have to ensure the first QPainter is destroyed
// first. Done.
// Default constructor
SvgWidgetClickable(QWidget* parentitem = nullptr);
// Construct with SVG from a file.
SvgWidgetClickable(const QString& filename,
QWidget* parentitem = nullptr);
// Sets the SVG image from a string.
void setSvgFromString(const QString& svg);
// Sets the SVG image from a file.
void setSvgFromFile(const QString& filename);
// Sets the widget's normal background colour.
void setBackgroundColour(const QColor& colour);
// Sets the widget's background colour when it's being pressed.
void setPressedBackgroundColour(const QColor& colour);
// Should mouse events go "through" this widget (i.e. treat it like an
void setTransparentForMouseEvents(bool transparent);
// Standard Qt widget overrides.
virtual void mousePressEvent(QMouseEvent* event) override;
virtual void mouseMoveEvent(QMouseEvent* event) override;
virtual void mouseReleaseEvent(QMouseEvent* event) override;
virtual void paintEvent(QPaintEvent* event) override;
// "Start of mouse/touch press."
// "A click has occurred." Press -> release = click.
QColor m_background_colour; // normal background colour
QColor m_pressed_background_colour; // background colour whilst being pressed
bool m_pressed; // being pressed?
bool m_pressing_inside; // being pressed and cursor remains inside us?