I have a custom QStyledItemDelegate that paints a QPixmap in a particular column. When that cell is hovered over with the mouse, I would like to paint it differently.
Below is my paint event, which does paint the cell correctly when not State_MouseOver. However, it changes the color when I hover anywhere on the row. How can I make it change only when the mouse is hovering over the cell with the pixmap in it?
void myDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
Q_ASSERT(index.isValid());
switch(index.column()) {
case DAY_COLUMN:
{
QSize btnSize = QSize(option.rect.height() * .9, option.rect.height() * .9);
QRect r = option.rect;
int x = r.right() - btnSize.width() - 10;
int y = r.top();
QRect btnRect = QRect(x, y, btnSize.width(), btnSize.height());
QPixmap pixmap(":/icons/edit.png");
// If hovered over, change color.
if(option.state & QStyle::State_MouseOver) {
auto mask = pixmap.createMaskFromColor(QColor("Black"), Qt::MaskOutColor);
pixmap.fill(QColor("Red"));
pixmap.setMask(mask);
}
painter->drawPixmap(btnRect, pixmap, pixmap.rect());
return;
}
/*.... draw other column(s) as appropriate ...*/
}
}
I'm using this delegate on all rows withing a QTreeView.
Qt 5.12
It can be because the selection behavior of the QTreeView is QAbstractItemView::SelectRows by default.
You can change it using:
m_tree_view.setSelectionBehavior(QAbstractItemView::SelectItems);
See more:
QAbstractItemView::SelectionBehavior
QTreeView source code
Related
I extented a QStyledItemDelegate to draw some pixmaps on the right side of a QTreeView. This works well, however, I realized that the pixmaps can be in front of the text if it gets too long.
So I tried to draw a rectangle of the same color as the background before drawing my pixmap.
void MyItemDelegate::paint(
QPainter *painter,
const QStyleOptionViewItem &option,
const QModelIndex &index) const
{
...
QStyledItemDelegate::paint(painter, option, index);
...
QStyleOptionViewItem opt = option;
initStyleOption(&opt, index);
...
painter->fillRect(rect, opt.backgroundBrush);
painter->drawPixmap(topLeft, pixmap);
}
I know that all variables are correct except opt.backgroundBrush. It's always invisible black, with or without the initStyleOption call.
Then I started to check the value of opt.state and opt.features to pick the color myself. I had some success with the alternating color (QStyleOptionViewItem::Alternate) but it's starting to get long and tedious because there are other states (hover and selected) and other OS that may have other states. There must be a simpler way.
So, my question is: How can I get the actual color that will be used to paint the row when I'm in the paint method? Or, do you have any other clean way to avoid this situation?
As suggested by #G.M. I used the QItemDelegate class instead of QStyledItemDelegate and I do have more control on the drawing process. Notably because of the added protected functions like drawDisplay. Overriding this method, I can adjust the "display rectangle" to a smaller size than what was calculated by Qt.
void ActionsItemDelegate::drawDisplay(
QPainter *painter,
const QStyleOptionViewItem &option,
const QRect &rect,
const QString &text) const
{
const int minX = ...; // x position of the left-most icon
const int iconsWidth = rect.width() - (minX - rect.x());
QItemDelegate::drawDisplay(painter, option, rect.adjusted(0, 0, -iconsWidth, 0), text);
}
The drawback is that the UI changes when using QStyledItemDelegate. I don't know how to get the benefits of both: normal style and more controls.
I may process differently. I won't start by calling:
QStyledItemDelegate::paint(painter, option, index);
in the first place.
Then, the important part: if you know how much icons there are on your items, you could calculate the bounding rectangle.
How do you know how many icons you have ? Maybe by calling something like:
bool hasIcon = index->data(YourAPP::HasIcons).toBool();
You could have something like this in your delegate:
void MyItemDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const {
...
QStyleOptionViewItem o = option;
initStyleOption(&o, index);
bool hasIcon = index->data(YourModel::HasIcons).toBool();
// or
bool hasCustomRole1 = index->data(YourModel::Role1).toBool();
bool hasCustomRole2 = index->data(YourModel::Role2).toBool();
if (hasIcon) {
// width of your icons, can be like o.rect.height() * numbers of icons
int width = 0;
// shrink your first rectangle
o.rect.adjust(0, 0, -width, 0);
// create a second rectangle
QStyleOptionViewItem o2 = option;
initStyleOption(&o2, index);
o2.rect.adjust(width, 0, 0, 0);
// paint your icons
...
painter->drawPixmap(o2, pixmap);
} else {
QStyledItemDelegate::paint(painter, option, index);
}
I have a QTableView that works very well, the first column holds some thumbnails, in each cell of this column the thumbnails are vertically centered, but not horizontally centered.
Do I really need to use a delegate?
If yes, How to center them horizontally using QStyledItemDelegate?
Construct your own delegate and inherit QStyledItemDelegate. Override the paint method.
Then do something like this:
void
MyDelegate::paint(QPainter* painter, const QStyleOptionViewItem& option,
const QModelIndex& index) const
{
QPixmap pixmap;
pixmap.load("Your pixmap file path");
pixmap = pixmap.scaled(option.rect.width(), option.rect.height(), Qt::KeepAspectRatio);
// Position our pixmap
const int x = option.rect.center().x() - pixmap.rect().width() / 2;
const int y = option.rect.center().y() - pixmap.rect().height() / 2;
if (option.state & QStyle::State_Selected) {
painter->fillRect(option.rect, option.palette.highlight());
}
painter->drawPixmap(QRect(x, y, pixmap.rect().width(), pixmap.rect().height()), pixmap);
}
Drawing by yourself is not necessary, but a custom delegate - is. The styled item delegate uses the style's control element drawing code to draw a CE_ItemViewItem - see the source code for Qt 5.5.0. The drawing code takes the style option's decorationAlignment member into account. Unfortunately, there's no data role that would pass that alignment to the styles's implementation. Instead, you have to override the alignment in your delegate:
class DecorationAligningDelegate : public QStyledItemDelegate {
Q_OBJECT
Qt::Alignment const m_alignment;
public:
explicit DecorationAligningDelegate(Qt::Alignment alignment, QObject * parent = 0) :
QStyledItemDelegate(parent), m_alignment(alignment) {}
Qt::Alignment alignment() const { return m_alignment; }
void paint(QPainter * painter, const QStyleOptionViewItem & option, const QModelIndex & index) const {
auto opt = option;
opt.decorationAlignment = m_alignment;
QStyledItemDelegate::paint(painter, opt, index);
}
};
Then, to center the thumbnails:
view.setItemDelegateForColumn(0,
new DecorationAligningDelegate(Qt::AlignHCenter, &view));
//or
view->setItemDelegateForColumn(0,
new DecorationAligningDelegate(Qt::AlignHCenter, view));
If you really wished to paint it all yourself, even though it's unnecessary, the rectangle of the item to be painted is given in the style option (option.rect). To draw the pixmap centered in the item's rectangle, you could do as follows:
QStyleOption option;
QPixmap pix;
QPainter painter;
...
painter.save();
auto loc = option.rect.center() - pix.rect().center()
painter.drawPixmap(loc, pix);
painter.restore();
I will just leave my version that literary is a combination of the two answers.
class DecorationAligningDelegate : public QStyledItemDelegate
{
Q_OBJECT
public:
explicit DecorationAligningDelegate(Qt::Alignment alignment, QObject *parent = nullptr)
: QStyledItemDelegate(parent), m_alignment(alignment) {}
Qt::Alignment alignment() const { return m_alignment; }
void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
QIcon icon = QIcon(qvariant_cast<QIcon>(index.data(Qt::DecorationRole)));
if (option.state & QStyle::State_Selected)
{
painter->fillRect(option.rect, option.palette.highlight());
}
icon.paint(painter, option.rect, m_alignment);
}
private:
Q_DISABLE_COPY(VDecorationAligningDelegate)
Qt::Alignment const m_alignment;
};
I assume you define your item like this:
auto *item = new QTableWidgetItem();
item->setIcon(QIcon("Your pixmap file path"));
Don't forget about setting a delegate.
I need to customize the QCheckbox like this: add a square between the checkbox and the text :
So to do this, I inherit QCheckBox and override paintEvent(QPaintEvent*):
void customCheckBox::paintEvent(QPaintEvent*){
QPainter p(this);
QStyleOptionButton opt;
initStyleOption(&opt);
style()->drawControl(QStyle::CE_CheckBox,&opt,&p,this);
QFontMetrics font= this->fontMetrics();// try to get pos by bounding rect of text, but it ain't work :p
QRectF rec = font.boundingRect(this->text());
p.fillRect(rect,QBrush(QColor(125,125,125,128)));
p.drawRect(rect);
}
I have a problem that I don't know how the position to place the QRectF rec. And I can't set the size too small, eg: it will disappear when size of rec < QSize(10,10).
Any ideas are appreciated.
PS: I use OpenSUSE 13.1 with Qt 4.8.5
The main idea is to copy default implementation of checkbox drawing and modify it according to your needs. We get label rectangle in default implementation, so we just need to draw new element in this place and shift label to the right. Also we need to adjust size hint so that both new element and default content fit in minimal size.
class CustomCheckBox : public QCheckBox {
Q_OBJECT
public:
CustomCheckBox(QWidget* parent = 0) : QCheckBox(parent) {
m_decoratorSize = QSize(16, 16);
m_decoratorMargin = 2;
}
QSize minimumSizeHint() const {
QSize result = QCheckBox::minimumSizeHint();
result.setWidth(result.width() + m_decoratorSize.width() + m_decoratorMargin * 2);
return result;
}
protected:
void paintEvent(QPaintEvent*) {
QPainter p(this);
QStyleOptionButton opt;
initStyleOption(&opt);
QStyleOptionButton subopt = opt;
subopt.rect = style()->subElementRect(QStyle::SE_CheckBoxIndicator, &opt, this);
style()->drawPrimitive(QStyle::PE_IndicatorCheckBox, &subopt, &p, this);
subopt.rect = style()->subElementRect(QStyle::SE_CheckBoxContents, &opt, this);
p.fillRect(QRect(subopt.rect.topLeft() + QPoint(m_decoratorMargin, 0),
m_decoratorSize), QBrush(Qt::green));
subopt.rect.translate(m_decoratorSize.width() + m_decoratorMargin * 2, 0);
style()->drawControl(QStyle::CE_CheckBoxLabel, &subopt, &p, this);
if (opt.state & QStyle::State_HasFocus) {
QStyleOptionFocusRect fropt;
fropt.rect = style()->subElementRect(QStyle::SE_CheckBoxFocusRect, &opt, this);
fropt.rect.setRight(fropt.rect.right() +
m_decoratorSize.width() + m_decoratorMargin * 2);
style()->drawPrimitive(QStyle::PE_FrameFocusRect, &fropt, &p, this);
}
}
private:
QSize m_decoratorSize;
int m_decoratorMargin;
};
Note that this solution may be not portable because checkboxes are drawn with drastic differences on different platforms. I tested it on Windows only. I used default implementation provided by QCommonStyle.
QAbstractButton has a property called icon, which is drawn differently depending on what subclass is instantiated.
Luckily for you, the position of the icon in a QCheckBox is exactly in the position you illustrated in your picture.
So, all you need to do for your customised QCheckBox is define what the icon should be and the default paintEvent will take care of the rest.
For simplicity's sake, I'm assuming the icon size should be the same size as the check box itself:
class CheckBox : public QCheckBox {
public:
CheckBox() {
QStyleOptionButton option;
initStyleOption(&option);
QSize indicatorSize = style()->proxy()->subElementRect(QStyle::SE_CheckBoxIndicator, &option, this).size();
QPixmap pixmap(indicatorSize);
pixmap.fill(Qt::green);
QIcon icon;
icon.addPixmap(pixmap);
setIcon(icon);
}
};
I have tested this on a Windows 8.1 machine with Qt 5.2.1 and it works.
I am using multiple QToolButtons in a custom QGridLayout widget. The buttons are set to display icon + text based on an assigned default QAction. The only issue is that the content (icon + text) is always left-aligned.
The content (icon + text, marked as a red box in the screenshot), should be center in the button (indicated by the blue box).
For most cases this is just fine, given that Qt automatically tries to render that button with the minimal size. However I am stretching the button to fit nicely into my QGridLayout.
QToolButton* pButton = new QToolButton(0);
pButton->addDefaultAction(pAction);
pButton->setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
pButton->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Preferred);
QGridLayout *pActionAreaLayout = new QGridLayout;
pActionAreaLayout->addWidget(pSomeOtherWidget, 0, 0, 1, 2);
pActionAreaLayout->addWidget(pButton , 1, 0, 1, 1);
Is there a way to force the content to be centered in the button?
PS: I found the following comment in another forum, which however seems quite invasive and is not really clear to me yet:
You can try doing the horizontal alignment using a stylesheet, but you probably have to implement a QStyle proxy and reimplement drawControl() for QStyle::CE_ToolButtonLabel
Or derive from QToolButton, overwrite paintEvent() and call the style for everything other than the label.
As I suggest in answer to you another question. https://stackoverflow.com/a/28630318/1917249 Do not use QToolButton, just use QPushButton, and add popup menu if needed.
Then you wont have different sizes of QToolButton and QPushButton widgets. And you will have centered icon and text.
Popupmenu can be easily added to QPushButton ( only small arrow wont be shown )
QPushButton *pushButton = new QPushButton(toolAction->icon(), "PushButton", window);
// window - widget where button is placed ( to get correct QMenu position )
QObject::connect(pushButton, &QPushButton::released, [window, pushButton, action](){
QMenu menu;
menu.addAction(action);
QPoint pos = window->mapToGlobal(pushButton3->pos());
pos += QPoint(0, pushButton->height());
menu.exec(pos);
});
Or you can subclass QPushButton and add Popup menu handling there. Much better then try to center text with icon in QToolButton or have in same size of QPushButton and QToolButton
For complex example please see my answer: https://stackoverflow.com/a/28630318/1917249
The following class does the job for me:
class CenteredToolButtonStyle : public QProxyStyle
{
Q_OBJECT
public:
CenteredToolButtonStyle(QToolButton* b, const QSize& sIcon);
virtual void drawItemPixmap(QPainter *painter, const QRect &rect, int, const QPixmap &pixmap) const
override { m_pic = pixmap; m_ny = rect.y(); Draw(painter); }
virtual void drawItemText(QPainter *painter, const QRect &rect, int flags, const QPalette &pal, bool enabled,
const QString &text, QPalette::ColorRole textRole = QPalette::NoRole) const override;
void Draw(QPainter *painter) const;
const QToolButton* B;
const QSize SICON;
mutable QString m_s;
mutable QPixmap m_pic;
mutable QRect m_r;
mutable int m_nf, m_ny;
mutable bool m_bEnabled;
mutable QPalette m_pal;
mutable QPalette::ColorRole m_textRole;
};
CenteredToolButtonStyle::CenteredToolButtonStyle(QToolButton* b, const QSize& sIcon)
: QProxyStyle(), B(b), SICON(sIcon), m_nf(0), m_bEnabled(true), m_ny(0)
{
b->setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
setParent(b);
}
void CenteredToolButtonStyle::drawItemText(QPainter *painter, const QRect &rect, int flags, const QPalette &pal,
bool enabled, const QString &text, QPalette::ColorRole textRole/* = QPalette::NoRole*/) const
{
m_s = text;
m_r = rect;
m_nf = flags | Qt::AlignCenter;
m_bEnabled = enabled;
m_pal = pal;
m_textRole = textRole;
Draw(painter);
}
void CenteredToolButtonStyle::Draw(QPainter *painter) const
{
if (m_ny) {
if (m_r.y() != m_ny) return;
auto r = m_r;
r.adjust(-SICON.width() - 8, m_ny = 0, -itemTextRect(B->fontMetrics(), m_r, m_nf, m_bEnabled, m_s).width(), 0);
QProxyStyle::drawItemPixmap(painter, r, Qt::AlignCenter, m_pic);
}
QProxyStyle::drawItemText(painter, m_r, m_nf, m_pal, m_bEnabled, m_s, m_textRole);
}
Sample use:
foreach(auto b, ui.mainToolBar->findChildren<QToolButton*>())
b->setStyle(new CenteredToolButtonStyle(b, ui.mainToolBar->iconSize()));
I am setting a QPixmap to a QStandardItem:
QStandardItem* item = new QStandardItem();
item->setData( pixmap, Qt::DecorationRole );
Then I do appendRow() and add item to the Model.
I display all the pixmaps in the Model in a QListView.
How do I set a thin border to only the 1st item (image) in the ListView ?
Subclass QStyledItemDelegate and override it´s paint function. Use this to paint a border to your item. Then set that delegate to your QListView.
Example:
void MyDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
if(index.row() == 0)
{
painter->setPen(QPen(Qt::red, 2));
painter->drawRect(option.rect.x()+1, option.rect.y(), option.rect.width()-1, option.rect.height());
}
QStyledItemDelegate::paint(painter, option, index);
}
And to set the delegate for your QListView:
listView->setItemDelegate(new MyDelegate);
You don't necessarely have to check the row in the paint function. You can just set the delegate for a specific row:
listView->setItemDelegateForRow(0, new MyDelegate);