Im using ImGUI and I want to implement a layer menu for the images and to move them im using
Drag to reorder items in a vector.
Sometimes it works just fine but others the images just jumps from the current position to a random one.
for (int i = 0; i < this->Images->size(); i++) {
ImGui::Image((void*)(intptr_t)this->Images->at(i).texture, ImVec2(100 * temp_percentage, 100 * temp_percentage));
ImGui::SameLine();
ImGui::Selectable(this->Images->at(i).name.c_str());
if (ImGui::IsItemActive() && !ImGui::IsItemHovered())
{
int n_next = i + (ImGui::GetMouseDragDelta(0).y < 0.f ? -1 : 1);
if (n_next >= 0 && n_next < this->Images->size())
{
std::swap(this->Images->at(i), this->Images->at(n_next));
*this->CurrentImage = this->Images->front();
centerImage();
ImGui::ResetMouseDragDelta();
}
}
ImGui::Separator();
}
The problem lies at !ImGui::IsItemHovered(), there is small spacing between the lines (cell, selectable,... ), so when the mouse hovers over that spacing, the item isn't hovered but still is actived, and therefore will execute the swap and reset mouse delta multiple times making it goes to the top or bottom of the list. This will also happen if the mouse goes out of the table/window bounds.
To make the problem more visible, you can make the spacing bigger using ImGui::GetStyle().ItemSpacing.y = 50.f;.
To actually fix the problem, you'll have to calculate the item index using the mouse position, here is a way to do it, tho not perfect but it works.
ImGuiStyle& style = ImGui::GetStyle();
ImVec2 windowPosition = ImGui::GetWindowPos();
ImVec2 cursorPosition = ImGui::GetCursorPos();
// this is not a pixel perfect position
// you can try to make it more accurate by adding some offset
ImVec2 itemPosition (
windowPosition.x + cursorPosition.x,
windowPosition.y + cursorPosition.y - style.ItemSpacing.y
);
for (int i = 0; i < this->Images->size(); i++) {
ImGui::Image((void*)(intptr_t)this->Images->at(i).texture, ImVec2(100 * temp_percentage, 100 * temp_percentage));
ImGui::SameLine();
ImGui::Selectable(this->Images->at(i).name.c_str());
if (ImGui::IsItemActive() && ImGui::IsMouseDragging(0))
{
int n_next = floorf((ImGui::GetMousePos().y - itemPosition.y) / itemHeight);
if (n_next != i && n_next >= 0 && n_next < this->Images->size())
{
std::swap(this->Images->at(i), this->Images->at(n_next));
*this->CurrentImage = this->Images->front();
centerImage();
}
}
ImGui::Separator();
}
There is also another problem in your code, if there are multiple items with the same name, ImGui::IsItemActive() will return true for all of them if one is actived.
You can fix this easily by adding ##some_unique_string after the name, for example ImGui::Selectable("Image#image_1") will just display Image.
I have read many questions about this topic but all I have found are either unanswered, do not do what I want, or simply do not work.
My problem is that of maintaining a height to width ratio while resizing my main window. So far I have seen propositions to override 'QLayout' and use 'heightForWidth' to perform the deed, to use the 'resizeEvent' call back to change the size hint, and to use the 'resizeEvent' call back to resize the window.
The first two options I mentioned only work in the examples for dragging width; I want a user to be able to drag width or height. The second of the two I attempted to adapt for my purposes but it causes my code to crash (the first relies on the 'heightForWidth' function and I cannot find a 'widthForHeight' function {The comments in this thread support my conclusion: How to maintain widgets aspect ratio in Qt?}). The third option was what I originally attempted but has a lot of bugs: most of the time the window snaps back to its original size, having rapidly transitioned between that and where it should be while dragging the border with the mouse.
The attempt which causes a crash:
void window::resizeEvent(QResizeEvent *event)
{
//window::resizeEvent(event); causes crash
if ((this->width() * 5 / 8) > (this->height() + 1)
|| (this->width() * 5 / 8) < (this->height() - 1))
{
updateGeometry();
}
}
QSize window::sizeHint() const
{
QSize s = size();
if (lastWidth != s.width())
{
s.setHeight((s.width()*5)/8);
//s.setWidth(window::sizeHint().width());
}
else if (lastHeight != s.height())
{
s.setWidth((s.height()*8)/5);
//s.setHeight(window::sizeHint().height());
}
return s;
}
The attempt which has bugs:
void window::resizeEvent(QResizeEvent *)
{
//If the window does not have the correct aspect ratio
//This should be false if this function caused the resize event,
// preventing a loop
if ((this->width() * 5 / 8) > (this->height() + 1)
|| (this->width() * 5 / 8) < (this->height() - 1))
{
int currentHeight = this->height();
int currentWidth = this->width();
//Change the dimension the user did not to match the user's change.
if (lastWidth != currentWidth)
{
lastWidth = currentWidth;
currentHeight = currentWidth * 5/8;
lastHeight = currentHeight;
}
else
{
lastHeight = currentHeight;
currentWidth = currentHeight * 8/5;
lastWidth = currentWidth;
}
//update the change
this->resize(currentWidth,currentHeight);
}
}
I have a simple script which displays one button (which is a png image) and when the user clicks it the application quits.
But i want to add multiple buttons which is where im finding my current thinking will lead to a very long if:else situation and I am wondering if that is the only way.
This is how i have my current menu set up in a main.cpp file.
bool handle_mouse_leftClick(int x, int y, SDL_Surface *button) {
if( ( ( mouseX > x ) && ( mouseX < x + button->w ) ) && ( ( mouseY > y ) && ( mouseY < y + button->h ) ) ) {
return true;
} else {
return false;
}
}
This is my detection function.
Below is my main function which acts as my game loop, i've removed non relevant code to keep it easier to follow:
//menu button
SDL_Surface *button;
button = IMG_Load("button.png");
while(!quit){
//handle events
while( SDL_PollEvent( &event ) ){
switch(event.type){
case SDL_QUIT: quit = true; break;
case SDL_MOUSEBUTTONDOWN:
if (event.button.button == SDL_BUTTON_LEFT) {
if(handle_mouse_leftClick(btnx,btny,button)){
quit = true;
}
}
break;
}
}
The issue is should my main.cpp have all this checking going on, is going to get very long very quickly when i add more buttons so I'm wondering if I have missed a trick to simplify my efforts?
When you get right down to the basic logic/computation, I would say the answer is "no", you haven't missed any tricks. I've never found a way around checking each target one at a time - at least in terms of computation. You could make your code cleaner a lot of ways. You could have a GuiElement class that exposes a "bool IsIn( int x, int y )" method. Then your big case statement would look more like:
bool handle_mouse_leftClick(int x, int y, SDL_Surface *button)
{
if (Button1.IsIn( mouseX, mouseY )
{
// do this
}
else if (Button2.IsIn( mouseX, mouseY ))
{
// do that
}
else
{
return false;
}
}
You could then further reduce amount code with a list or table:
int handle_mouse_leftClick(int x, int y, SDL_Surface *button)
{
for (unsigned int i = 0; i < buttonList.size(); i++
{
if (buttonList[i].IsIn( mouseX, mouseY ))
{
return i; // return index of button pressed
}
return -1; // nothing pressed
}
}
But it's still ultimately looking at each rectangle one at a time.
Couple caveats:
I don't think there's much real computational overhead in checking the hit boxes of each item - unless you're doing it at some crazy high frame rate.
Sure, you could optimize the checking with some kind of spatial index (like a b-tree or quad-tree organized by the locations of the buttons on the screen), but ... see #1. ;-)
If instead of 10 or 15 buttons/controls you have THOUSANDS then you will likely want to do #2 because #1 will no longer be true.
********* Update ***********
Here's a brief sample of a class that could be used for this. As far as .h vs main.cpp, the typical approach is to put the header in a "Button.h" and the implementation (code) in a "Button.cpp", but you could just put this at the top of main.cpp to get started - it has all the logic right in the class definition.
You'll notice I didn't really write any new code. The "IsIn()" test is your logic verbatim, I just changed the variable names to match the class. And since you already have a single button, I'm assuming you can reuse the code that renders that button the Render() method.
And lastly, if is not something you're familiar with, you don't have to create a list/vector at all. The code the renders the buttons could just call "okButton.Render()", followed by "cancelButton.Render()".
Sample "button" class:
class Button
{
private:
int m_x, m_y; // coordinates of upper left corner of control
int m_width, m_height; // size of control
public:
Button(int x, int y, int width, int height, const char* caption)
{
m_x = x;
m_y = y;
m_width = width;
m_height = height;
// also store caption in variable of same type you're using now for button text
}
bool IsIn( int mouseX, int mouseY )
{
if (((mouseX > m_x) && (mouseX < m_x + m_width))
&& ((mouseY > m_y) && (mouseY < m_y + m_height ) ) ) {
return true;
} else {
return false;
}
}
void Render()
{
// use the same code you use now to render the button in OpenGL/SDL
}
};
Then to create it/them (using the list approach):
Button okButton( 10, 10, 100, 50, "OK" );
buttonList.push_back( okButton );
Button cancelButton( 150, 10, 100, 50, "Cancel" );
buttonList.push_back( cancelButton );
And in your render loop:
void Update()
{
for (unsigned int i = 0; i < buttonList.size(); i++
{
buttonList[i].Render();
}
}
I'm making a program that let me click on the center of two concentric circles and, by mouse move, change it's position and i can do the same with it's radii.
The thing is that the mouse movement is followed by a delay response from the circles drawing making the radius follow the mouse instead of being exactly in the same position during the movement.
Would you guys know how to make it work like that? pin point following by the drawing.
a bit of the code that treats the mouse clicking and movements:
void DemoApp::OnLButtonDown(FLOAT pixelX, FLOAT pixelY)
{
SetCapture(m_hwnd);
mouseRegion = DPIScale::PixelsToDips(pixelX, pixelY);
FLOAT xDifference = centerCircles.x - mouseRegion.x;
FLOAT yDifference = centerCircles.y - mouseRegion.y;
FLOAT distanceToCenter = sqrtf(xDifference*xDifference + yDifference*yDifference);
if(distanceToCenter < 10.0f)
{
centerMove = true;
minimumRadiusCircleMove = false;
maximumRadiusCircleMove = false;
}
else if((distanceToCenter > (minimumRadius - 1.0f)) && (distanceToCenter < (minimumRadius + 1.0f)))
{
minimumRadiusCircleMove = true;
centerMove = false;
maximumRadiusCircleMove = false;
}
else if((distanceToCenter > (maximumRadius - 1.0f)) && (distanceToCenter < (maximumRadius + 1.0f)))
{
maximumRadiusCircleMove = true;
centerMove = false;
minimumRadiusCircleMove = false;
}
else
{
centerMove = false;
minimumRadiusCircleMove = false;
maximumRadiusCircleMove = false;
}
InvalidateRect(m_hwnd, NULL, FALSE);
}
void DemoApp::OnMouseMove(int pixelX, int pixelY, DWORD flags)
{
if (flags & MK_LBUTTON)
{
if(centerMove)
{
centerCircles = DPIScale::PixelsToDips(pixelX, pixelY);
FLOAT distanceLeftToCenterCircles = abs(centerCircles.x - bitmapTopLeft);
FLOAT distanceTopToCenterCircles = abs(centerCircles.y - bitmapTopRight);
percentageFromLeft = distanceLeftToCenterCircles / displaySizeWidth;
percentageFromTop = distanceTopToCenterCircles / displaySizeHeight;
}
else if(minimumRadiusCircleMove)
{
radiusSelection = DPIScale::PixelsToDips(pixelX, pixelY);
FLOAT xDifference = centerCircles.x - radiusSelection.x;
FLOAT yDifference = centerCircles.y - radiusSelection.y;
minimumRadius = sqrtf(xDifference*xDifference + yDifference*yDifference);
minimumRadiusPercentage = minimumRadius/(displaySizeWidth/2);
}
else if(maximumRadiusCircleMove)
{
radiusSelection = DPIScale::PixelsToDips(pixelX, pixelY);
FLOAT xDifference = centerCircles.x - radiusSelection.x;
FLOAT yDifference = centerCircles.y - radiusSelection.y;
maximumRadius = sqrtf(xDifference*xDifference + yDifference*yDifference);
maximumRadiusPercentage = maximumRadius/(displaySizeWidth/2);
}
InvalidateRect(m_hwnd, NULL, FALSE);
}
}
void DemoApp::OnLButtonUp()
{
ReleaseCapture();
}
According to MSDN ( http://msdn.microsoft.com/en-us/library/dd145002%28v=vs.85%29.aspx ) InvalidateRect doesn’t cause the window to be repainted until the next WM_PAINT and "The system sends a WM_PAINT message to a window whenever its update region is not empty and there are no other messages in the application queue for that window." so it’s not immediate.
I found a possible solution on MSDN here Drawing Without the WM_PAINT Message
i've found a solution to that problem!
It's way simple than expected, all you got to do is add a flag while creating the render target, that way the mousemove will respond way faster:
the flag is: D2D1_PRESENT_OPTIONS_IMMEDIATELY.
// Create Direct2d render target.
hr = m_pD2DFactory->CreateHwndRenderTarget(
D2D1::RenderTargetProperties(),
D2D1::HwndRenderTargetProperties(m_hwnd, size, D2D1_PRESENT_OPTIONS_IMMEDIATELY),
&m_pRenderTarget
);
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)