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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;
}
A friend of mine and I are currently trying to make a game in C++ using Qt. Our current problem is that we need to fetch text from a QGraphicsTextItem on a button mousePressEvent. In the game menu it is possible to choose how many players there are, therefore we've placed a QGraphicsTextItem in a for-loop to make it possible for all the users to type in their names. Because of the for-loop, we don't have names for every single text item object so we can store the names. We've managed to store all the memory addresses to the objects using QMap, but we don't know how to get the text of of this. We don't even know if this is the best way to do it.
GameInfo.h
class GameInfo {
public:
GameInfo();
int players;
QStringList names = (QStringList() // Default player names. This array should be overwritten by the custom names
<< "Player 1"
<< "Player 2"
<< "Player 3"
<< "Player 4"
<< "Player 5"
<< "Player 6"
<< "Player 7");
QMap<int, QGraphicsTextItem**> textBoxMap; // This is where we store all the addresses
};
Game.cpp
QGraphicsRectItem * overviewBox = new QGraphicsRectItem();
overviewBox->setRect(0, 0, 782, 686);
scene->addItem(overviewBox);
int faceNo = 0;
// Create the player selection section
for(int i = 1; i <= players; i++) { // "players" is defined another place in the code, and is an integer between 1 and 6
Container * selContainer = new Container();
selContainer->Selection(i, faceNo);
selContainer->setPos(50, 70 + 110 * (i - 1));
scene->addItem(selContainer);
Container * ovContainer = new Container(overviewBox);
ovContainer->Overview(i, faceNo);
ovContainer->setPos(0, 0 + 110 * (i - 1));
info->textBoxMap.insert(i, &selContainer->textBox->playerText); // This is where we save the addresses
}
Selection.cpp
extern Game * game;
Container::Container(QGraphicsItem * parent): QGraphicsRectItem(parent) {
}
void Container::Selection(int nPlayers, int sPiceNo, QGraphicsItem *parent) {
QString numName = QString::number(nPlayers);
setRect(0, 0, 672, 110);
this->setPen(Qt::NoPen); // Removes border
int posY = this->rect().height() / 2;
QSignalMapper * signalMapper = new QSignalMapper(this);
arrowL = new Arrow(0, posY - 32, 0, this);
piece = new Piece(sPiceNo, 96, posY - 32, 1, 1, this);
arrowR = new Arrow(192, posY - 32, 1, this);
textBox = new TextBox(game->info->names[nPlayers - 1], true, this);
textBox->setPos(288, posY - 32);
lockBtn = new Button("Lock", 96, 32, this);
connect(lockBtn, SIGNAL(clicked()), signalMapper, SLOT(map()));
signalMapper->setMapping(lockBtn, nPlayers);
connect(signalMapper, SIGNAL(mapped(int)), this, SLOT(lock(int)));
lockBtn->setPos(640, posY - 16);
}
void Container::Overview(int ovPlayers, int ovPiceNo, QGraphicsItem * parent) {
// Some code...
}
void Container::lock(int nPlayer) {
qDebug() << game->info->textBoxMap[nPlayer];
qDebug() << game->info->names[nPlayer - 1];
game->info->names[nPlayer - 1] = **game->info->textBoxMap[nPlayer].toPlainText(); // This line causes an error
}
The error that occurs because of the last line looks like this:
error: no match for 'operator=' (operand types are 'QString' and 'QGraphicsTextItem')
game->info->names[nPlayer - 1] = **game->info->textBoxMap[nPlayer];
^
TextBox.cpp
TextBox::TextBox(QString text, bool editable, QGraphicsItem * parent): QGraphicsRectItem(parent) {
this->editable = editable;
// Draw the textbox
setRect(0, 0, 320, 64);
if(!editable) {
this->setPen(Qt::NoPen); // Removes border
}
else if(editable) {
QBrush brush;
brush.setStyle(Qt::SolidPattern);
brush.setColor(QColor(255, 255, 255, 255));
setBrush(brush);
}
// Draw the text
playerText = new QGraphicsTextItem(text, this);
int fontId = QFontDatabase::addApplicationFont(":/fonts/built_titling_bd.ttf");
QString family = QFontDatabase::applicationFontFamilies(fontId).at(0);
QFont built(family, 25);
playerText->setFont(built);
int xPos = 0;
int yPos = rect().height() / 2 - playerText->boundingRect().height() / 2;
playerText->setPos(xPos,yPos);
}
My question is how do i fetch the text from the QGraphicsTextItem?
You should try to learn a bit more about C++ before trying to develop a game imo. (Having public variables is against OO's and C++ paradigm)
But here is what you are looking for:
http://doc.qt.io/qt-5/qgraphicstextitem.html#toPlainText
EDIT:
If you are not able to debug some line of code, I could only recommend to try to seperate your code in order to have a minimum of call in a single line. I haven't try the code bellow, but that how you should try to debug your code:
void Container::lock(int nPlayer)
{
qDebug() << game->info->textBoxMap[nPlayer];
qDebug() << game->info->names[nPlayer - 1];
QGraphicsTextItem **value = game->info->textBoxMap.value(nPlayer, nullptr);
game->info->names[nPlayer - 1] =(*value)->toPlainText();
}
I am trying to create a text wrapper function using SDL1.2 + SDL_TTF. I am aware that SDL2.0 already has a readily available text wrapping function (TTF_RenderText_Blended_Wrapped) but I am using SDL1.2, therefore I am trying to create the wrapping function manually.
Basically I have two surfaces, one which is the wrapper surface and the other one a temporary surface which contains the rendered string. The rendered string is a string between two white spaces taken from the entire string which is to be wrapped. Each temporary surface (string part) is rendered and blit onto the wrapper surface and automatically jumps to the next line if the wrapper width is exceeded.
The string is eventually wrapped properly, however the problem comes with the wrapper surface. Initially I create a colored surface with SDL_CreateRGBSurface() because to my understanding I cannot blit the string parts onto an empty surface. After the wrapping, I want to remove the unused space on the wrapper surface so that the the surface is transparent besides the text.
For this I used color-keying but noticed that that is a poor solution since it also removes some of the text color. My other attempt was to use the alpha values on both surfaces but using SDL_SetAlpha() but this somehow resulted into the same result with the text color being all wrong.
Below is an example of the code I wrote, I would really appreciate some alternative ideas or solutions.
TTF_Font* textFont = nullptr;
SDL_Color textColor = {0, 0, 0};
std::string wrapperText = "This text is to be wrapped with transparency";
SDL_Surface* wrapperSurface = nullptr;
SDL_Rect wrapperRect = {0, 0, 160, 50};
std::string tempString = "";
SDL_Surface* tempSurface = nullptr;
SDL_Rect tempRect = {0, 0, 0, 0};
int lineWidthPx = 0;
int lineHeightPx = 0;
int textWidthPx = 0;
int textHeightPx = 0;
std::size_t textBegin = 0;
std::size_t textEnd = 0;
textFont = TTF_OpenFont("res/fonts/Nunito-Black.ttf", 14);
wrapperSurface = SDL_CreateRGBSurface(SDL_HWSURFACE, wrapperRect.w, wrapperRect.h, 32, 255, 255, 255, 255);
SDL_SetAlpha(wrapperSurface, SDL_SRCALPHA | SDL_RLEACCEL, SDL_ALPHA_TRANSPARENT);
while (textEnd < wrapperText.size())
{
textBegin = textEnd + 1;
textEnd = wrapperText.find(" ", textBegin);
if (textEnd == std::string::npos)
textEnd = wrapperText.size(); // Reached end of text
tempString = wrapperText.substr(textBegin - 1, textEnd - textBegin + 1);
TTF_SizeText(textFont, tempString.c_str(), &textWidthPx, &textHeightPx);
lineWidthPx += textWidthPx;
if (lineWidthPx > wrapperRect.w)
{
tempString = wrapperText.substr(textBegin, textEnd - textBegin);
lineWidthPx = 0 + textWidthPx;
lineHeightPx += textHeightPx; // Next line
if (lineHeightPx > wrapperRect.h)
break; // Text is too large for wrapper
}
tempSurface = TTF_RenderUTF8_Solid(textFont, tempString.c_str(), textColor);
SDL_SetAlpha(tempSurface, SDL_SRCALPHA | SDL_RLEACCEL, SDL_ALPHA_OPAQUE);
tempRect = { static_cast<Sint16>(lineWidthPx-textWidthPx), static_cast<Sint16>(lineHeightPx), static_cast<Uint16>(textWidthPx), static_cast<Uint16>(textHeightPx) };
SDL_BlitSurface(tempSurface, NULL, wrapperSurface, &tempRect);
}
TTF_CloseFont(textFont);
textFont = nullptr;
// Remove temporary surface
SDL_FreeSurface(tempSurface);
tempSurface = nullptr;
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.
I am writing a Visual Basic IDE, and I need to add lines numbers to QTextEdit and highlight current line. I have found this tutorial, but it is written in Java and I write my project in C++.
I know that Qt tutorial recommends using QPlainTextEdit for text editor implementations, and that the question (except as mentioned in the title), is more general than dealing (absolutely) with a QTextEdit widget, but I succeeded in implementing the behaviour (line numbers + current line number highlight), and I think this might be helpful for some people (like me) who really want to keep going with the Rich Text widget, and want to share my implementation (which is far from perfect - quite fast coded...).
LineNumberArea.h : (Same as "QPlainTextEdit" tutorial)
class LineNumberArea : public QWidget
{
Q_OBJECT
public:
LineNumberArea(QTextEdit *editor);
QSize sizeHint() const;
protected:
void paintEvent(QPaintEvent *event);
private:
QTextEdit *codeEditor;
};
LineNumberArea.cpp : (Same as "QPlainTextEdit" tutorial)
LineNumberArea::LineNumberArea(QTextEdit *editor) : QWidget(editor) {
codeEditor = editor;
}
QSize LineNumberArea::sizeHint() const {
return QSize(((QTextEditHighlighter *)codeEditor)->lineNumberAreaWidth(), 0);
}
void LineNumberArea::paintEvent(QPaintEvent *event) {
((QTextEditHighlighter *)codeEditor)->lineNumberAreaPaintEvent(event);
}
>> qtextedithighlighter.h :
class QTextEditHighlighter : public QTextEdit
{
Q_OBJECT
public:
explicit QTextEditHighlighter(QWidget *parent = 0);
int getFirstVisibleBlockId();
void lineNumberAreaPaintEvent(QPaintEvent *event);
int lineNumberAreaWidth();
signals:
public slots:
void resizeEvent(QResizeEvent *e);
private slots:
void updateLineNumberAreaWidth(int newBlockCount);
void updateLineNumberArea(QRectF /*rect_f*/);
void updateLineNumberArea(int /*slider_pos*/);
void updateLineNumberArea();
private:
QWidget *lineNumberArea;
};
>> qtextedithighlighter.cpp :
#include "qtextedithighlighter.h"
QTextEditHighlighter::QTextEditHighlighter(QWidget *parent) :
QTextEdit(parent)
{
// Line numbers
lineNumberArea = new LineNumberArea(this);
///
connect(this->document(), SIGNAL(blockCountChanged(int)), this, SLOT(updateLineNumberAreaWidth(int)));
connect(this->verticalScrollBar(), SIGNAL(valueChanged(int)), this, SLOT(updateLineNumberArea/*_2*/(int)));
connect(this, SIGNAL(textChanged()), this, SLOT(updateLineNumberArea()));
connect(this, SIGNAL(cursorPositionChanged()), this, SLOT(updateLineNumberArea()));
///
updateLineNumberAreaWidth(0);
}
int QTextEditHighlighter::lineNumberAreaWidth()
{
int digits = 1;
int max = qMax(1, this->document()->blockCount());
while (max >= 10) {
max /= 10;
++digits;
}
int space = 13 + fontMetrics().width(QLatin1Char('9')) * (digits);
return space;
}
void QTextEditHighlighter::updateLineNumberAreaWidth(int /* newBlockCount */)
{
setViewportMargins(lineNumberAreaWidth(), 0, 0, 0);
}
void QTextEditHighlighter::updateLineNumberArea(QRectF /*rect_f*/)
{
QTextEditHighlighter::updateLineNumberArea();
}
void QTextEditHighlighter::updateLineNumberArea(int /*slider_pos*/)
{
QTextEditHighlighter::updateLineNumberArea();
}
void QTextEditHighlighter::updateLineNumberArea()
{
/*
* When the signal is emitted, the sliderPosition has been adjusted according to the action,
* but the value has not yet been propagated (meaning the valueChanged() signal was not yet emitted),
* and the visual display has not been updated. In slots connected to this signal you can thus safely
* adjust any action by calling setSliderPosition() yourself, based on both the action and the
* slider's value.
*/
// Make sure the sliderPosition triggers one last time the valueChanged() signal with the actual value !!!!
this->verticalScrollBar()->setSliderPosition(this->verticalScrollBar()->sliderPosition());
// Since "QTextEdit" does not have an "updateRequest(...)" signal, we chose
// to grab the imformations from "sliderPosition()" and "contentsRect()".
// See the necessary connections used (Class constructor implementation part).
QRect rect = this->contentsRect();
lineNumberArea->update(0, rect.y(), lineNumberArea->width(), rect.height());
updateLineNumberAreaWidth(0);
//----------
int dy = this->verticalScrollBar()->sliderPosition();
if (dy > -1) {
lineNumberArea->scroll(0, dy);
}
// Addjust slider to alway see the number of the currently being edited line...
int first_block_id = getFirstVisibleBlockId();
if (first_block_id == 0 || this->textCursor().block().blockNumber() == first_block_id-1)
this->verticalScrollBar()->setSliderPosition(dy-this->document()->documentMargin());
// // Snap to first line (TODO...)
// if (first_block_id > 0)
// {
// int slider_pos = this->verticalScrollBar()->sliderPosition();
// int prev_block_height = (int) this->document()->documentLayout()->blockBoundingRect(this->document()->findBlockByNumber(first_block_id-1)).height();
// if (dy <= this->document()->documentMargin() + prev_block_height)
// this->verticalScrollBar()->setSliderPosition(slider_pos - (this->document()->documentMargin() + prev_block_height));
// }
}
void QTextEditHighlighter::resizeEvent(QResizeEvent *e)
{
QTextEdit::resizeEvent(e);
QRect cr = this->contentsRect();
lineNumberArea->setGeometry(QRect(cr.left(), cr.top(), lineNumberAreaWidth(), cr.height()));
}
int QTextEditHighlighter::getFirstVisibleBlockId()
{
// Detect the first block for which bounding rect - once translated
// in absolute coordinated - is contained by the editor's text area
// Costly way of doing but since "blockBoundingGeometry(...)" doesn't
// exists for "QTextEdit"...
QTextCursor curs = QTextCursor(this->document());
curs.movePosition(QTextCursor::Start);
for(int i=0; i < this->document()->blockCount(); ++i)
{
QTextBlock block = curs.block();
QRect r1 = this->viewport()->geometry();
QRect r2 = this->document()->documentLayout()->blockBoundingRect(block).translated(
this->viewport()->geometry().x(), this->viewport()->geometry().y() - (
this->verticalScrollBar()->sliderPosition()
) ).toRect();
if (r1.contains(r2, true)) { return i; }
curs.movePosition(QTextCursor::NextBlock);
}
return 0;
}
void QTextEditHighlighter::lineNumberAreaPaintEvent(QPaintEvent *event)
{
this->verticalScrollBar()->setSliderPosition(this->verticalScrollBar()->sliderPosition());
QPainter painter(lineNumberArea);
painter.fillRect(event->rect(), Qt::lightGray);
int blockNumber = this->getFirstVisibleBlockId();
QTextBlock block = this->document()->findBlockByNumber(blockNumber);
QTextBlock prev_block = (blockNumber > 0) ? this->document()->findBlockByNumber(blockNumber-1) : block;
int translate_y = (blockNumber > 0) ? -this->verticalScrollBar()->sliderPosition() : 0;
int top = this->viewport()->geometry().top();
// Adjust text position according to the previous "non entirely visible" block
// if applicable. Also takes in consideration the document's margin offset.
int additional_margin;
if (blockNumber == 0)
// Simply adjust to document's margin
additional_margin = (int) this->document()->documentMargin() -1 - this->verticalScrollBar()->sliderPosition();
else
// Getting the height of the visible part of the previous "non entirely visible" block
additional_margin = (int) this->document()->documentLayout()->blockBoundingRect(prev_block)
.translated(0, translate_y).intersect(this->viewport()->geometry()).height();
// Shift the starting point
top += additional_margin;
int bottom = top + (int) this->document()->documentLayout()->blockBoundingRect(block).height();
QColor col_1(90, 255, 30); // Current line (custom green)
QColor col_0(120, 120, 120); // Other lines (custom darkgrey)
// Draw the numbers (displaying the current line number in green)
while (block.isValid() && top <= event->rect().bottom()) {
if (block.isVisible() && bottom >= event->rect().top()) {
QString number = QString::number(blockNumber + 1);
painter.setPen(QColor(120, 120, 120));
painter.setPen((this->textCursor().blockNumber() == blockNumber) ? col_1 : col_0);
painter.drawText(-5, top,
lineNumberArea->width(), fontMetrics().height(),
Qt::AlignRight, number);
}
block = block.next();
top = bottom;
bottom = top + (int) this->document()->documentLayout()->blockBoundingRect(block).height();
++blockNumber;
}
}
Hope this can help...
Here's the equivalent tutorial in C++:
Qt4: http://doc.qt.io/qt-4.8/qt-widgets-codeeditor-example.html
Qt5: http://doc.qt.io/qt-5/qtwidgets-widgets-codeeditor-example.html
I was looking for a line numbers painting solution for QTextEdit (not QPlainTextEdit), and I found the previous answer with sample code for QTextEdit is useful, but when we set custom line height in QTextEdit's associated SyntaxHighligher, it doesn't work reliably.
To fix that problem, I figured out a simpler way to determine the y coordinate of each block rect by using this code:
// Here is the key to obtain the y coordinate of the block start
QTextCursor blockCursor(block);
QRect blockCursorRect = this->cursorRect(blockCursor);
And then we can draw line number of each block via:
painter.drawText(-5, blockCursorRect.y() /* + a little offset to align */,
m_lineNumberArea->width(), fixedLineHeight,
Qt::AlignRight, number);
This seems much simpler and more reliable than calculating the block y coordinate by adding previous block height up.
Hope it helps for someone who is looking for similar solutions.
Here is an easy example to determine the text positions for drawing line numbers for the QTextEdit derived classes.
code_browser::code_browser(QWidget *parent): QTextBrowser(parent)
, m_line_number_area(new LineNumberArea(this))
, m_show_line_numbers(false)
{
connect(document(), SIGNAL(blockCountChanged(int)), this, SLOT(updateLineNumberAreaWidth(int)));
connect(verticalScrollBar(), SIGNAL(valueChanged(int)), this, SLOT(vertical_scroll_value(int)));
connect(this, SIGNAL(updateRequest(QRect,int)), this, SLOT(updateLineNumberArea(QRect,int)));
connect(this, SIGNAL(cursorPositionChanged()), this, SLOT(highlightCurrentLine()));
updateLineNumberAreaWidth(blockCount());
highlightCurrentLine();
}
void code_browser::vertical_scroll_value(int value)
{
Q_EMIT updateRequest(contentsRect(), value);
}
void code_browser::lineNumberAreaPaintEvent(QPaintEvent *event)
{
QPainter painter(m_line_number_area);
painter.fillRect(event->rect(), Qt::lightGray);
int top = 0;
QTextBlock block = firstVisibleBlock(top);
int blockNumber = block.blockNumber();
QRectF block_rect = blockBoundingRect(block);
int bottom = top + qRound(block_rect.height());
while (block.isValid() && top <= event->rect().bottom())
{
if (block.isVisible() && bottom >= event->rect().top())
{
QString number = QString::number(blockNumber + 1);
painter.setPen(Qt::black);
painter.drawText(0, top, m_line_number_area->width(), fontMetrics().height(), Qt::AlignRight, number);
}
block = block.next();
top = bottom;
block_rect = blockBoundingRect(block);
bottom = top + qRound(block_rect.height());
++blockNumber;
}
}
int code_browser::blockCount() const
{
return document()->blockCount();
}
QTextBlock code_browser::firstVisibleBlock(int& diff)
{
QPointF content_offset = contentOffset();
for (QTextBlock block = document()->begin(); block.isValid(); block = block.next())
{
if (block.isVisible())
{
QRectF block_rect = blockBoundingRect(block);
if (block_rect.top() >= content_offset.y())
{
diff = block_rect.top() - content_offset.y();
return block;
}
}
}
diff = -1;
return document()->begin();
}
QRectF code_browser::blockBoundingRect(const QTextBlock &block) const
{
QAbstractTextDocumentLayout *layout = document()->documentLayout();
return layout->blockBoundingRect(block);
}
QPointF code_browser::contentOffset() const
{
return QPointF(horizontalScrollBar()->value(), verticalScrollBar()->value());
}
Python's adaptation:
QTextEditHighlighter.py
from PySide6.QtCore import QRectF, QRect, Qt
from PySide6.QtGui import QResizeEvent, QTextCursor, QPaintEvent, QPainter, QColor
from PySide6.QtWidgets import QTextEdit, QApplication
from LineNumberArea import LineNumberArea
class QTextEditHighlighter(QTextEdit):
def __init__(self):
# Line numbers
QTextEdit.__init__(self)
self.lineNumberArea = LineNumberArea(self)
self.document().blockCountChanged.connect(self.updateLineNumberAreaWidth)
self.verticalScrollBar().valueChanged.connect(self.updateLineNumberArea)
self.textChanged.connect(self.updateLineNumberArea)
self.cursorPositionChanged.connect(self.updateLineNumberArea)
self.updateLineNumberAreaWidth(0)
def lineNumberAreaWidth(self):
digits = 1
m = max(1, self.document().blockCount())
while m >= 10:
m /= 10
digits += 1
space = 13 + self.fontMetrics().horizontalAdvance('9') * digits
return space
def updateLineNumberAreaWidth(self, newBlockCount: int):
self.setViewportMargins(self.lineNumberAreaWidth(), 0, 0, 0)
def updateLineNumberAreaRect(self, rect_f: QRectF):
self.updateLineNumberArea()
def updateLineNumberAreaInt(self, slider_pos: int):
self.updateLineNumberArea()
def updateLineNumberArea(self):
"""
When the signal is emitted, the sliderPosition has been adjusted according to the action,
but the value has not yet been propagated (meaning the valueChanged() signal was not yet emitted),
and the visual display has not been updated. In slots connected to self signal you can thus safely
adjust any action by calling setSliderPosition() yourself, based on both the action and the
slider's value.
"""
# Make sure the sliderPosition triggers one last time the valueChanged() signal with the actual value !!!!
self.verticalScrollBar().setSliderPosition(self.verticalScrollBar().sliderPosition())
# Since "QTextEdit" does not have an "updateRequest(...)" signal, we chose
# to grab the imformations from "sliderPosition()" and "contentsRect()".
# See the necessary connections used (Class constructor implementation part).
rect = self.contentsRect()
self.lineNumberArea.update(0, rect.y(), self.lineNumberArea.width(), rect.height())
self.updateLineNumberAreaWidth(0)
dy = self.verticalScrollBar().sliderPosition()
if dy > -1:
self.lineNumberArea.scroll(0, dy)
# Addjust slider to alway see the number of the currently being edited line...
first_block_id = self.getFirstVisibleBlockId()
if first_block_id == 0 or self.textCursor().block().blockNumber() == first_block_id-1:
self.verticalScrollBar().setSliderPosition(dy-self.document().documentMargin())
# # Snap to first line (TODO...)
# if first_block_id > 0:
# slider_pos = self.verticalScrollBar().sliderPosition()
# prev_block_height = (int) self.document().documentLayout().blockBoundingRect(self.document().findBlockByNumber(first_block_id-1)).height()
# if (dy <= self.document().documentMargin() + prev_block_height)
# self.verticalScrollBar().setSliderPosition(slider_pos - (self.document().documentMargin() + prev_block_height))
def resizeEvent(self, event: QResizeEvent):
QTextEdit.resizeEvent(self, event)
cr = self.contentsRect()
self.lineNumberArea.setGeometry(QRect(cr.left(), cr.top(), self.lineNumberAreaWidth(), cr.height()))
def getFirstVisibleBlockId(self) -> int:
# Detect the first block for which bounding rect - once translated
# in absolute coordinated - is contained by the editor's text area
# Costly way of doing but since "blockBoundingGeometry(...)" doesn't
# exists for "QTextEdit"...
curs = QTextCursor(self.document())
curs.movePosition(QTextCursor.Start)
for i in range(self.document().blockCount()):
block = curs.block()
r1 = self.viewport().geometry()
r2 = self.document().documentLayout().blockBoundingRect(block).translated(
self.viewport().geometry().x(), self.viewport().geometry().y() - (
self.verticalScrollBar().sliderPosition()
)).toRect()
if r1.contains(r2, True):
return i
curs.movePosition(QTextCursor.NextBlock)
return 0
def lineNumberAreaPaintEvent(self, event: QPaintEvent):
self.verticalScrollBar().setSliderPosition(self.verticalScrollBar().sliderPosition())
painter = QPainter(self.lineNumberArea)
painter.fillRect(event.rect(), Qt.lightGray)
blockNumber = self.getFirstVisibleBlockId()
block = self.document().findBlockByNumber(blockNumber)
if blockNumber > 0:
prev_block = self.document().findBlockByNumber(blockNumber - 1)
else:
prev_block = block
if blockNumber > 0:
translate_y = -self.verticalScrollBar().sliderPosition()
else:
translate_y = 0
top = self.viewport().geometry().top()
# Adjust text position according to the previous "non entirely visible" block
# if applicable. Also takes in consideration the document's margin offset.
if blockNumber == 0:
# Simply adjust to document's margin
additional_margin = self.document().documentMargin() -1 - self.verticalScrollBar().sliderPosition()
else:
# Getting the height of the visible part of the previous "non entirely visible" block
additional_margin = self.document().documentLayout().blockBoundingRect(prev_block) \
.translated(0, translate_y).intersect(self.viewport().geometry()).height()
# Shift the starting point
top += additional_margin
bottom = top + int(self.document().documentLayout().blockBoundingRect(block).height())
col_1 = QColor(90, 255, 30) # Current line (custom green)
col_0 = QColor(120, 120, 120) # Other lines (custom darkgrey)
# Draw the numbers (displaying the current line number in green)
while block.isValid() and top <= event.rect().bottom():
if block.isVisible() and bottom >= event.rect().top():
number = f"{blockNumber + 1}"
painter.setPen(QColor(120, 120, 120))
if self.textCursor().blockNumber() == blockNumber:
painter.setPen(col_1)
else:
painter.setPen(col_0)
painter.drawText(-5, top,
self.lineNumberArea.width(), self.fontMetrics().height(),
Qt.AlignRight, number)
block = block.next()
top = bottom
bottom = top + int(self.document().documentLayout().blockBoundingRect(block).height())
blockNumber += 1
if __name__ == '__main__':
app = QApplication([])
w = QTextEditHighlighter()
w.show()
app.exec()
LineNumberArea.py
from PySide6.QtCore import QSize
from PySide6.QtWidgets import QWidget
class LineNumberArea(QWidget):
def __init__(self, editor):
QWidget.__init__(self, editor)
self.codeEditor = editor
def sizeHint(self) -> QSize:
return QSize(self.codeEditor.lineNumberAreaWidth(), 0)
def paintEvent(self, event):
self.codeEditor.lineNumberAreaPaintEvent(event)