Bar code label printing using html-Qt - c++

I have managed to generate bar-code on a QLabel. I have tried QPainter and I could not get properly aligned output. My label size is 50*25 mm for a label ,one row contain two label.
This is my code for printing label.
I want to know that, is there any solution to print label using html. So that I can design very well.
QPrinter printer1;
QList<QPrinterInfo> printerList = QPrinterInfo::availablePrinters() ;
for(int r=0; r<printerList.size();++r)
{
if(printerList[r].printerName() == "TSC TE200")
{
QPageSize pageSize(QSizeF(45.0,70.0),QPageSize::Millimeter,"",QPageSize::ExactMatch);
QPrinter PRINTER(printerList[r],QPrinter::PrinterResolution);
PRINTER.setOrientation(QPrinter::Portrait);
PRINTER.setPageSize(pageSize);
PRINTER.setFullPage(true);
PRINTER.setOutputFormat(QPrinter::NativeFormat);
// int id = QFontDatabase::addApplicationFont("/Applications/untitledfolder/free3of9.ttf");
// QFontDatabase::applicationFontFamilies(id).at(0);
QFont barcodefont;
barcodefont.setFamily("Code 128");
barcodefont.setWeight(QFont::Normal);
barcodefont.setPointSize(60);
QFontMetrics fntm(barcodefont);
QPainter painter2;
if(!painter2.begin(&PRINTER))
return;
int x1 = printer1.paperRect().x() + printer1.width()/2 -
fntm.width("123456789")/2;enter code here
int y1 = printer1.paperRect().y();
int w1 = fntm.width("123456789");
int h1 = fntm.height()/4;
int x11 = printer1.paperRect().x() + printer1.width() - fntm.width("123456789")/2;
int y11 = printer1.paperRect().y();
int w11 = fntm.width("123456789");
int h11 = fntm.height()/4;
QRect rect10 = QRect(x1,y1,w1,h1);
QRect rect20 = QRect(x11,y11,w11,h11);
painter2.setFont(barcodefont);
painter2.drawText(rect10,Qt::AlignLeft,"123456789");
painter2.end();
break;
}
}
Sorry about my English. I'm not fluent in English.Thanks in advance.

Related

QGroupBox's child restricts shrink the form

I have a multiple screen video player, and I just want to keep 16:9 ratio. There is a qgroupbox as a container of a qwidget which plays video in it. I also use qgroupbox to show selected frame by painting border to green. I can't do this on qwidget because rendered video overlaps that. When I have done with resize, I emit a signal with mouseup event to be able to informed about the resize operation completed. Then I calculate new bounds for qwidget to keep 16:9 ratio and apply this values for qwidget. Here is the image to show you how my app looks like:
And here is the code that I use to resize qwidgets:
void playBack::OnWindowResized()
{
float ratio = 16.0f / 9.0f;
float w = playBackplayer_contList.at(0)->size().width(); //qgroupbox's width
float h = playBackplayer_contList.at(0)->size().height();//qgroupbox's height
float currentRatio = w / h;
float newW = 0;
float newH = 0;
if (currentRatio > ratio)
{
newH = h;
newW = h*ratio;
}
else if (currentRatio < ratio)
{
newW = w;
newH = w / ratio;
}
qDebug() << "NEW WIDGET SIZE: " << (int)newW << " x " << (int)newH;
for (int i = 0; i < playBackplayer_widgtList.count(); i++)
{
playBackplayer_widgtList.at(i)->setMinimumSize(newW, newH);
//playBackplayer_widgtList.at(i)->resize(newW, newH);
}
}
This code works perfectly when I enlarge form, but When I want to shrink, It doesn't allow me to do that. Because I set a minimum value for qwidgets. If I don't use setMinimumSize, use resize(w,h) instead, than orientation problems occur. And here is a example for this issue:
This code below shows ctor and this is where I set the layout:
playBack::playBack()
{
playback_player_1_widget = new QWidget;
playback_player_2_widget = new QWidget;
playback_player_3_widget = new QWidget;
playback_player_4_widget = new QWidget;
playback_player_1_widget_cont = new QGroupBox;
playback_player_2_widget_cont = new QGroupBox;
playback_player_3_widget_cont = new QGroupBox;
playback_player_4_widget_cont = new QGroupBox;
playBackplayer_widgtList.append(playback_player_1_widget);
playBackplayer_widgtList.append(playback_player_2_widget);
playBackplayer_widgtList.append(playback_player_3_widget);
playBackplayer_widgtList.append(playback_player_4_widget);
playBackplayer_contList.append(playback_player_1_widget_cont);
playBackplayer_contList.append(playback_player_2_widget_cont);
playBackplayer_contList.append(playback_player_3_widget_cont);
playBackplayer_contList.append(playback_player_4_widget_cont);
int rowcnt = 0;
int colcnt = 0;
for (int i = 0; i < 4; i++)
{
playBackplayer_contList.at(i)->setStyleSheet(QString("border:1px solid #000;background-color:#000;"));
playBackplayer_widgtList.at(i)->setStyleSheet(QString("background-color:#f00;"));
QGridLayout* layout = new QGridLayout;
layout->setRowStretch(0, 1);
layout->setColumnStretch(0, 1);
layout->setRowStretch(2, 1);
layout->setColumnStretch(2, 1);
playBackplayer_widgtList.at(i)->setMinimumWidth(100);
playBackplayer_widgtList.at(i)->setMinimumHeight(100);
playBackplayer_widgtList.at(i)->setMaximumWidth(10000);
playBackplayer_widgtList.at(i)->setMaximumHeight(10000);
layout->addWidget(playBackplayer_widgtList.at(i),1,1);
layout->setMargin(0);
layout->setSpacing(0);
playBackplayer_contList.at(i)->setLayout(layout);
mainLayout->addWidget(playBackplayer_contList.at(i), colcnt, rowcnt);
rowcnt++;
if (rowcnt % 2 == 0)
{
rowcnt = 0;
colcnt++;
}
playBackplayer_widgtList.at(i)->setAcceptDrops(true);
}
}
I have tried various things, I have tried to set size 0 for qwidget before resize, (in mousedownevent) that didn't work, I have tried deleting layout for qgroupbox, after resize happens, create new layout and set it for groupbox, that didn't work, I have tried layout()->adjustSize(), update(), repaint(), all that stuff didn't work. What am I missing? I need helps from you. Any help would be appreciated. Thank you in advance.
Do away with the grid layout inside the container group boxes. Instead, align and resize the video widget with setGeometry
Here is a simple subclass of QGroupBox I made that keeps your desired ratio and always stays in the center:
class RatioGroupBox : public QGroupBox{
Q_OBJECT
public:
RatioGroupBox(QWidget *parent = nullptr) : QGroupBox (parent){
setFlat(true);
setStyleSheet("border:1px solid #000;background-color:#000;");
setMinimumSize(100, 100);
setMaximumSize(10000, 10000);
ratio = 16.0f/9.0f;
ratioWidget = new QWidget(this);
ratioWidget->setStyleSheet("background: #f00;");
ratioWidget->setAcceptDrops(true);
}
protected:
void resizeEvent(QResizeEvent *){//or you can use your own resize slot
float w = width();
float h = height();
float currentRatio = w/h;
float newW(0);
float newH(0);
if (currentRatio > ratio){
newH = h;
newW = h*ratio;
}
else if (currentRatio < ratio){
newW = w;
newH = w / ratio;
}
ratioWidget->setGeometry((w-newW)/2, (h-newH)/2, newW, newH);
}
private:
QWidget *ratioWidget;
float ratio;
};
Your entire ctor will become something like:
playBack::playBack()
{
for(int r=0; r<2; r++){
for(int c=0; c<2; c++){
RatioGroupBox* playback_player_cont = new RatioGroupBox;
mainLayout->addWidget(playback_player_cont, c, r);
playBackplayer_contList.append(playback_player_cont);
}
}
}
You can of course access your video widgets by exposing ratioWidget any way you like. Either by making it public or creating a getter function.

Qt Window incorrect size until user event

I'm creating a screen where users can add certain tiles to use in an editor, but when adding a tile the window does not correctly resize to fit the content. Except that when I drag the window or resize it even just a little then it snaps to the correct size immediately.
And when just dragging the window it snaps to the correct size.
I tried using resize(sizeHint()); which gave me an incorrect size and the following error, but the snapping to correct size still happens when resizing/dragging.
QWindowsWindow::setGeometry: Unable to set geometry 299x329+991+536 on QWidgetWindow/'TileSetterWindow'. Resulting geometry: 299x399+991+536 (frame: 8, 31, 8, 8, custom margin: 0, 0, 0, 0, minimum size: 259x329, maximum size: 16777215x16777215).
I also tried using updateGeometry() and update(), but it didn't seem to do much if anything.
When setting the window to fixedSize it will immediately resize, but then the user cannot resize the window anymore. What am I doing wrong here and where do I start to solve it?
Edit
Minimal verifiable example and the .ui file.
selected_layout is of type Flowlayout
The flowlayout_placeholder_1 is only there because I can't place a flowlayout directly into the designer.
Edit2
Here is a minimal Visual Studio example. I use Visual Studio for Qt development. I tried creating a project in Qt Creator, but I didn't get that to work.
Edit3
Added a little video (80 KB).
Edit4
Here is the updated Visual Studio example. It has the new changes proposed by jpo38. It fixes the issue of the bad resizing. Though now trying to downsize the windows causes issues. They don't correctly fill up vertical space anymore if you try to reduce the horizontal space even though there is room for more rows.
Great MCVE, exactly what's needed to easily investigate the issue.
Looks like this FlowLayout class was not designed to have it's minimum size change on user action. Layout gets updated 'by chance' by QWidget kernel when the window is moved.
I could make it work smartly by modifying FlowLayout::minimumSize() behaviour, here are the changes I did:
Added QSize minSize; attribute to FlowLayout class
Modifed FlowLayout::minimumSize() to simply return this attribute
Added a third parameter QSize* pMinSize to doLayout function. This will be used to update this minSize attribute
Modified doLayout to save computed size to pMinSize parameter if specified
Had FlowLayout::setGeometry pass minSize attribute to doLayout and invalidate the layout if min size changed
The layout then behaves as expected.
int FlowLayout::heightForWidth(int width) const {
const int height = doLayout(QRect(0, 0, width, 0), true,NULL); // jpo38: set added parameter to NULL here
return height;
}
void FlowLayout::setGeometry(const QRect &rect) {
QLayout::setGeometry(rect);
// jpo38: update minSize from here, force layout to consider it if it changed
QSize oldSize = minSize;
doLayout(rect, false,&minSize);
if ( oldSize != minSize )
{
// force layout to consider new minimum size!
invalidate();
}
}
QSize FlowLayout::minimumSize() const {
// jpo38: Simply return computed min size
return minSize;
}
int FlowLayout::doLayout(const QRect &rect, bool testOnly,QSize* pMinSize) const {
int left, top, right, bottom;
getContentsMargins(&left, &top, &right, &bottom);
QRect effectiveRect = rect.adjusted(+left, +top, -right, -bottom);
int x = effectiveRect.x();
int y = effectiveRect.y();
int lineHeight = 0;
// jpo38: store max X
int maxX = 0;
for (auto&& item : itemList) {
QWidget *wid = item->widget();
int spaceX = horizontalSpacing();
if (spaceX == -1)
spaceX = wid->style()->layoutSpacing(QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Horizontal);
int spaceY = verticalSpacing();
if (spaceY == -1)
spaceY = wid->style()->layoutSpacing(QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Vertical);
int nextX = x + item->sizeHint().width() + spaceX;
if (nextX - spaceX > effectiveRect.right() && lineHeight > 0) {
x = effectiveRect.x();
y = y + lineHeight + spaceY;
nextX = x + item->sizeHint().width() + spaceX;
lineHeight = 0;
}
if (!testOnly)
item->setGeometry(QRect(QPoint(x, y), item->sizeHint()));
// jpo38: update max X based on current position
maxX = qMax( maxX, x + item->sizeHint().width() - rect.x() + left );
x = nextX;
lineHeight = qMax(lineHeight, item->sizeHint().height());
}
// jpo38: save height/width as max height/xidth in pMinSize is specified
int height = y + lineHeight - rect.y() + bottom;
if ( pMinSize )
{
pMinSize->setHeight( height );
pMinSize->setWidth( maxX );
}
return height;
}
I was having the same exact issue (albeit on PySide2 rather than C++).
#jpo38's answer above did not work directly, but it un-stuck me by giving me a new approach.
What worked was storing the last geometry, and using that geometry's width to calculate the minimum height.
Here is an untested C++ implementation based on the code in jpo38's answer (I don't code much in C++ so apologies in advance if some syntax is wrong):
int FlowLayout::heightForWidth(int width) const {
const int height = doLayout(QRect(0, 0, width, 0), true);
return height;
}
void FlowLayout::setGeometry(const QRect &rect) {
QLayout::setGeometry(rect);
// e-l: update lastSize from here
lastSize = rect.size();
doLayout(rect, false);
}
QSize FlowLayout::minimumSize() const {
// e-l: Call heightForWidth from here, my doLayout is doing things a bit differently with regards to margins, so might have to add or not add the margins here to the height
QSize size;
for (const QLayoutItem *item : qAsConst(itemList))
size = size.expandedTo(item->minimumSize());
const QMargins margins = contentsMargins();
size += QSize(margins.left() + margins.right(), margins.top() + margins.bottom());
size.setHeight(heightForWidth(qMax(lastSize.width(), size.width())));
return size;
}
int FlowLayout::doLayout(const QRect &rect, bool testOnly) const {
int left, top, right, bottom;
getContentsMargins(&left, &top, &right, &bottom);
QRect effectiveRect = rect.adjusted(+left, +top, -right, -bottom);
int x = effectiveRect.x();
int y = effectiveRect.y();
int lineHeight = 0;
for (auto&& item : itemList) {
QWidget *wid = item->widget();
int spaceX = horizontalSpacing();
if (spaceX == -1)
spaceX = wid->style()->layoutSpacing(QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Horizontal);
int spaceY = verticalSpacing();
if (spaceY == -1)
spaceY = wid->style()->layoutSpacing(QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Vertical);
int nextX = x + item->sizeHint().width() + spaceX;
if (nextX - spaceX > effectiveRect.right() && lineHeight > 0) {
x = effectiveRect.x();
y = y + lineHeight + spaceY;
nextX = x + item->sizeHint().width() + spaceX;
lineHeight = 0;
}
if (!testOnly)
item->setGeometry(QRect(QPoint(x, y), item->sizeHint()));
x = nextX;
lineHeight = qMax(lineHeight, item->sizeHint().height());
}
int height = y + lineHeight - rect.y() + bottom;
return height;
}

QtCharts - Background, foreground display

I want to display a QGraphicsRectItem in my QChartView. But the rectangle is displayed behind the lines series in the chart.
I've tried to do a setZValue(10), for example, on my QGraphicsRectItem and setZValue(0) on my QChart but it is still displayed behind.
Obviously I want the informations in the rectangle to be displayed in front of the series of the chart.
Constructor
StatisticsChartView::StatisticsChartView(QWidget *parent, QChart *chart)
: QChartView(chart, parent)
{
/* Create new chart */
_chart = new QChart();
chart = _chart;
_chart->setAnimationOptions(QChart::AllAnimations);
/* Default granularity */
m_iGranularity = DEFAULT_GRANULARITY;
/* Creating ellipse item which will display a circle when the mouse goes over the series */
m_ellipse = new QGraphicsEllipseItem(_chart);
penEllipse.setColor(QColor(0, 0, 0));
penBorder.setWidth(1);
m_ellipse->setPen(penEllipse);
/* Creating text item which will display the x and y value of the mouse position */
m_coordX = new QGraphicsSimpleTextItem(_chart);
m_coordY = new QGraphicsSimpleTextItem(_chart);
penBorder.setColor(QColor(0, 0, 0));
penBorder.setWidth(1);
m_coordX->setPen(penBorder);
m_coordY->setPen(penBorder);
m_rectHovered = new QGraphicsRectItem(_chart);
m_rectHovered->setBrush(QBrush(Qt::yellow));
m_coordHoveredX = new QGraphicsSimpleTextItem(m_rectHovered);
m_coordHoveredY = new QGraphicsSimpleTextItem(m_rectHovered);
penBorder.setColor(QColor(0, 0, 0));
penBorder.setWidth(1);
m_coordHoveredX->setPen(penBorder);
m_coordHoveredY->setPen(penBorder);
m_lineItemX = new QGraphicsLineItem(_chart);
m_lineItemY = new QGraphicsLineItem(_chart);
penLine.setColor(QColor(0, 0, 0));
penLine.setStyle(Qt::DotLine);
m_lineItemX->setPen(penLine);
m_lineItemY->setPen(penLine);
/* Enable zooming in the rectangle drawn with the left click of the mouse, zoom out with right click */
rubberBand = new QRubberBand(QRubberBand::Rectangle, this);
mousePressed = 0;
seriesHovered = false;
setMouseTracking(true);
_chart->setAcceptHoverEvents(true);
_chart->setZValue(50);
m_ellipse->setZValue(10); //so it is displayed over the series
m_coordHoveredX->setZValue(20); //so it is displayed over others
setRenderHint(QPainter::Antialiasing);
setChart(_chart);
}
Creation of series
void StatisticsChartView::drawCurve(bool bDrawScale)
{
int w = WIDTH;
int h = HEIGHT;
/* Creating series */
QLineSeries *lineFalse = new QLineSeries();
QLineSeries *lineAutomatic = new QLineSeries();
QLineSeries *lineOk = new QLineSeries();
QLineSeries *lineFalsePositive = new QLineSeries();
QLineSeries *lineManualTreatement = new QLineSeries();
QLineSeries *lineFalseNegative = new QLineSeries();
QList<QLineSeries*> lineSeriesList;
lineSeriesList << lineFalse << lineAutomatic << lineOk << lineFalsePositive << lineManualTreatement << lineFalseNegative;
QList<QString> nameSeriesList;
nameSeriesList << "False" << "Automatic" << "Ok" << "FalsePositive" << "ManualTreatement" << "FalseNegative";
QList<QVector<GraphPoint>> graphPointList;
graphPointList << gpFalse << gpDetected << gpOk << gpDetectedNotOk << gpManualTreatement << gpFalseNegative;
double graphX = 100.0 / (m_iGranularity);
bool pointsVisible = true;
for (int n = 0; n < lineSeriesList.count(); ++n)
{
/* Adding points to line series */
for (int i = 0; i < m_iGranularity + 1; ++i)
{
lineSeriesList[n]->append(i * graphX, (float)(graphPointList[n][i]).fValue * 100);
lineSeriesList[n]->setPointsVisible(pointsVisible);
lineSeriesList[n]->setName(nameSeriesList[n]);
}
}
_chart->legend()->setVisible(true);
_chart->legend()->setAlignment(Qt::AlignBottom);
/* Setting axis X and Y */
axisX = new QValueAxis();
axisY = new QValueAxis();
axisX->setRange(0, 100);
axisY->setRange(0, 100);
/* Adding line series to the chart and attaching them to the same axis */
for (int j = 0; j < lineSeriesList.count(); ++j)
{
_chart->addSeries(lineSeriesList[j]);
_chart->setAxisX(axisX, lineSeriesList[j]);
_chart->setAxisY(axisY, lineSeriesList[j]);
connect(lineSeriesList[j], SIGNAL(hovered(QPointF, bool)), this, SLOT(onSeriesHovered(QPointF, bool)));
}
_chart->resize(w, h);
return;
}
Drawing rectangle on chart
void StatisticsChartView::onSeriesHovered(QPointF point, bool state)
{
seriesHovered = state;
/* Updating the size of the rectangle */
if (mousePressed == 0 && seriesHovered == true)
{
/* x and y position on the graph */
qreal x = _chart->mapToPosition(point).x();
qreal y = _chart->mapToPosition(point).y();
/* x and y value on the graph from 0 to 100 for ou graph */
qreal xVal = point.x();
qreal yVal = point.y();
qreal maxX = axisX->max();
qreal minX = axisX->min();
qreal maxY = axisY->max();
qreal minY = axisY->min();
/* We don't want to display value outside of the axis range */
if (xVal <= maxX && xVal >= minX && yVal <= maxY && yVal >= minY)
{
m_coordHoveredX->setVisible(true);
m_coordHoveredY->setVisible(true);
m_rectHovered->setVisible(true);
m_ellipse->setVisible(true);
m_rectHovered->setRect(x - 31, y - 31, 30, 30);
qreal rectX = m_rectHovered->rect().x();
qreal rectY = m_rectHovered->rect().y();
qreal rectW = m_rectHovered->rect().width();
qreal rectH = m_rectHovered->rect().height();
/* We're setting the labels and nicely adjusting to chart axis labels (adjusting so the dot lines are centered on the label) */
m_coordHoveredX->setPos(rectX + rectW / 4 - 3, rectY + 1);
m_coordHoveredY->setPos(rectX + rectW / 4 - 3, rectY + rectH / 2 + 1);
/* Setting value to displayed with four digit max, float, 1 decimal */
m_coordHoveredX->setText(QString("%1").arg(xVal, 4, 'f', 1, '0'));
m_coordHoveredY->setText(QString("%1").arg(yVal, 4, 'f', 1, '0'));
m_ellipse->setRect(QRectF::QRectF(x, y, 10, 10));
m_ellipse->setPos(x, y);
m_ellipse->setBrush(QBrush(Qt::red));
}
else
{
/* We're not displaying information if out of the chart */
m_coordHoveredX->setVisible(false);
m_coordHoveredY->setVisible(false);
m_rectHovered->setVisible(false);
m_ellipse->setVisible(false);
}
}
else
{
/* We're not displaying information if series aren't hovered */
m_coordHoveredX->setVisible(false);
m_coordHoveredY->setVisible(false);
m_rectHovered->setVisible(false);
m_ellipse->setVisible(false);
}
}
You should try using a series especially for your rectangle.
Setting it as the last series, on your chart, to be above the other lines. And adding a legend or a callout for the text.

When I resize an image on Qt, how can I focus to middle point of widget?

I can change the resolution of an image with a slider. I use QGraphicsScene for displaying image.But the problem is when I resize image, I couldn't focus to a point.You can see my code here.
This is first part, so its for resize an image.It's working.
void MainWindow::on_sld_scale_valueChanged(int value) {
//for resize an image with slider
int w = m_image->width();
int h = m_image->height();
int new_w = (w * value)/100;
int new_h = (h * value)/100;
m_pixmap = QPixmap::fromImage(
m_image->scaled(new_w, new_h, Qt::KeepAspectRatio, Qt::FastTransformation));
This second part of my function.It is my algorithm for focus to middle point of widget but it doesn't work.
//for focus to middle point of widget
auto views = m_scene->views();
Q_ASSERT(views.size() == 1);
auto view = views.first();
int pos_x = view->horizontalScrollBar()->value();
int pos_y = view->verticalScrollBar()->value();
show_pixmap();
qDebug() << "x" << pos_x << "w" << view->width()
<< "sbw" << view->verticalScrollBar()->width()
<< "y" << pos_y << "h" << view->height()
<< "sbh" << view->horizontalScrollBar()->height();
int a = pos_x + (view->width()) + (view->verticalScrollBar()->width());
int b = pos_x + (view->height()) + (view->horizontalScrollBar()->height());
a = a * (value/100.0);
b = b * (value/100.0);
m_pixmap = QPixmap::fromImage(*m_image);
view->horizontalScrollBar()->setValue(a);
view->verticalScrollBar()->setValue(b);
}
This is my source code.I can resize the image but I can't focus to middle point.Can you help me to solve this problem?
Don't you mix QScrollBar::width to QScrollBar::maximum? They have difficult relation.
You better don't touch view's scroll bars. Try QGraphicsView::centerOn or even QGraphicsView::fitInView (did you mean "focus" to be "place to center of the view"?). Like this:
const qreal centerX = pixmapItem->x() + pixmapItem->width() / 2;
const qreal centerY = pixmapItem->y() + pixmapItem->height() / 2;
viewer->centerOn(centerX , centerY);
where pixmapItem is a QGraphicsPixmapItem.
As #mvidelgauz supposed, why don't you scale a QGraphicsPixmapItem in the scene? May this be a better solution to rescale it?
Don't recreate pixmap, use QGraphicsView's methods setResizeAnchor() and scale()

Custom placeholder in QLineEdit

I want to have a QLineEdit with the specific placeholder text format: it needs to have left aligned and right aligned text. Here is an example:
Any ideas?
Unfortunately, this seems to be all hard coded in void QLineEdit::paintEvent(QPaintEvent *) as follows:
if (d->shouldShowPlaceholderText()) {
if (!d->placeholderText.isEmpty()) {
QColor col = pal.text().color();
col.setAlpha(128);
QPen oldpen = p.pen();
p.setPen(col);
QRect ph = lineRect.adjusted(minLB, 0, 0, 0);
QString elidedText = fm.elidedText(d->placeholderText, Qt::ElideRight, ph.width());
p.drawText(ph, va, elidedText);
p.setPen(oldpen);
}
}
You could reimplement this on your own in a subclass if you wish.
Naturally, you could also "cheat" with space and font sizes, but that would require a bit more work, and would be nastier in the end, too, let alone long-term reliability.
You could also contribute to the Qt Project to make this class more flexible, but they could reject it with the reason of not being common case enough. It is up to the maintainer(s).
Thanks, #lpapp ! His advice is right. Here is the code, I created from the Qt sources suggested by #lpapp :
void LineEdit::paintEvent(QPaintEvent *e) {
QLineEdit::paintEvent(e);
if (!text().isEmpty()) {
return;
}
QPainter p(this);
QStyleOptionFrameV2 panel;
initStyleOption(&panel);
QRect r = style()->subElementRect(QStyle::SE_LineEditContents, &panel, this);
r.setX(r.x() + textMargins().left());
r.setY(r.y() + textMargins().top());
r.setRight(r.right() - textMargins().right());
r.setBottom(r.bottom() - textMargins().bottom());
QFontMetrics fm = fontMetrics();
int minLB = qMax(0, -fm.minLeftBearing());
int minRB = qMax(0, -fm.minRightBearing());
int vscroll = r.y() + (r.height() - fm.height() + 1) / 2;
static const int horizontalMargin = 2; // QLineEditPrivate::horizontalMargin
QRect lineRect(r.x() + horizontalMargin, vscroll, r.width() - 2*horizontalMargin, fm.height());
QRect ph = lineRect.adjusted(minLB, 0, -minRB, 0);
QColor col = palette().text().color();
col.setAlpha(128);
p.setPen(col);
QString left = fm.elidedText("left", Qt::ElideRight, ph.width());
Qt::Alignment leftAlignment = QStyle::visualAlignment(Qt::LeftToRight, QFlag(Qt::AlignLeft));
p.drawText(ph, leftAlignment, left);
QString right = fm.elidedText("right", Qt::ElideRight, ph.width());
Qt::Alignment rightAlignment = QStyle::visualAlignment(Qt::LeftToRight, QFlag(Qt::AlignRight));
p.drawText(ph, rightAlignment, right);
}
I don't know an easy way to do this. You could try to calculate the pixel width (using QFontMetrics) of both placeholder-parts and calculate the number of spaces you need to insert between the placeholder-parts to let them appear aligned. You wuld need to set/update the calculated placeholder whenever the size of the widget changes.