I'm trying to label the y-axis in a plot built using pango.
I'm unable to orient the text to run vertically up along the y-axis.
Relevant portion of code is:
#include <gtkmm.h>
Pango::FontDescription font;
cr->save(); // where cr is Glib::RefPtr<Cairo::Context> const &
cr->set_source_rgba(1.0,1.0,1.0,0.5);
font.set_family("Monospace");
font.set_style(Pango::STYLE_ITALIC);
font.set_weight(Pango::WEIGHT_BOLD);
font.set_absolute_size(20);
Glib::RefPtr<Pango::Layout> x_axis_label = this->create_pango_layout("x-axis label");
x_axis_label->set_font_description(font);
cr->move_to(0.38,0.465);
x_axis_label->show_in_cairo_context(cr);
// so far so good, renders as expected
// now trying to render the y-axis label
Glib::RefPtr<Pango::Context> t_y_axis_label_ctxt = x_axis_label->get_context();
Pango::Matrix p_matrix;
// apply some transformation
p_matrix.xx = 0.0;
p_matrix.xy = 1.0;
p_matrix.yx = 1.0;
p_matrix.yy = 0.0;
p_matrix.x0 = 0.0;
p_matrix.y0 = 0.0;
t_y_axis_label_ctxt->set_matrix(p_matrix);
Glib::RefPtr<Pango::Layout> y_axis_label = Pango::Layout::create(t_y_axis_label_ctxt);
y_axis_label->set_text("y-axis label"); // if this line of code is omitted I would expect, at least the text "x-axis label" to be rendered. But this does not happen.
y_axis_label->set_font_description(font);
cr->move_to(0.0,0.0);
y_axis_label->show_in_cairo_context(cr); // renders no output
cr->restore();
I suspect the problem has something to do with context that i retrieve from x-axis label, and the expected copy behaviour is not manifesting.
Are you sure you want to rotate the Pango context? I believe that functionality was introduced in the pre-Cairo days; now you would just rotate the Cairo context, like:
cr->save();
cr->rotate_degrees(90);
Glib::RefPtr<Pango::Layout> y_axis_label = this->create_pango_layout("y-axis label");
y_axis_label->set_font_description(font);
cr->move_to(...); // wherever you wanna put it
y_axis_label->show_in_cairo_context(cr);
cr->restore();
If you still don't see anything, make sure you are not moving the label out of the visible area.
Related
I am painting a block of text on a widget with QTextDocument::drawContents. My current goal is to intercept mouse events and emulate text selection. It's pretty clear how to handle the mouse, but displaying the result puzzles me a lot.
Just before we start: I can not use QLabel and let it handle selection on it's own (it has no idea how to draw unusual characters and messes up line height (https://git.macaw.me/blue/squawk/issues/59)), nor I can not use QTextBrowser there - it's just a message bubble, I'm not ready to sacrifice performance there.
There is a very rich framework around QTextDocument, but I can not find any way to make it color the background of some fragment of text that I would consider selected. Found a way to make a frame around a text, found a way to draw under-over-lined text, but it looks like there is simply just no way this framework can draw a background behind text.
I have tried doing this, to see if I can take selected fragment under some QTextFrame and set it's style:
QTextDocument* bodyRenderer = new QTextDocument();
bodyRenderer->setHtml("some text");
bodyRenderer->setTextWidth(50);
painter->setBackgroundMode(Qt::BGMode::OpaqueMode); //this at least makes it color background under all text
QTextFrameFormat format = bodyRenderer->rootFrame()->frameFormat();
format.setBackground(option.palette.brush(QPalette::Active, QPalette::Highlight));
bodyRenderer->rootFrame()->setFrameFormat(format);
bodyRenderer->drawContents(painter);
Nothing of this works too:
QTextBlock b = bodyRenderer->begin();
QTextBlockFormat format = b.blockFormat();
format.setBackground(option.palette.brush(QPalette::Active, QPalette::Highlight));
format.setProperty(QTextFormat::BackgroundBrush, option.palette.brush(QPalette::Active, QPalette::Highlight));
QTextCursor cursor(bodyRenderer);
cursor.setBlockFormat(format);
b = bodyRenderer->begin();
while (b.isValid() > 0) {
QTextLayout* lay = b.layout();
QTextLayout::FormatRange range;
range.format = b.charFormat();
range.start = 0;
range.length = 2;
lay->draw(painter, option.rect.topLeft(), {range});
b = b.next();
}
Is there any way I can make this framework do a simple thing - draw a selection background behind some text? If not - is there a way I can unproject cursor position into coordinate translation, like can I do reverse operation from QAbstractTextDocumentLayout::hitTest just to understand where to draw that selection rectangle myself?
You can use QTextCursor to change the background of the selected text. You only need to select one character at a time to keep the formatting. Here is an example of highlighting in blue (the color of the text is highlighted in white for contrast):
void MainWindow::paintEvent(QPaintEvent *event) {
QPainter painter(this);
painter.fillRect(contentsRect(), QBrush(QColor("white")));
QTextDocument document;
document.setHtml(QString("Hello <font size='20'>world</font> with Qt!"));
int selectionStart = 3;
int selectionEnd = selectionStart + 10;
QTextCursor cursor(&document);
cursor.setPosition(selectionStart);
while (cursor.position() < selectionEnd) {
cursor.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor); // select one symbol
QTextCharFormat selectFormat = cursor.charFormat();
selectFormat.setBackground(Qt::blue);
selectFormat.setForeground(Qt::white);
cursor.setCharFormat(selectFormat); // set format for selection
cursor.movePosition(QTextCursor::Right, QTextCursor::MoveAnchor, 1);
}
document.drawContents(&painter, contentsRect());
QMainWindow::paintEvent(event);
}
I've looked here:
https://www.amcharts.com/docs/v4/reference/xycursor/
and tried this
chart.cursor.fontSize = "14";
chart.cursor.fill = am4core.color("#ff0000");
chart.cursor.fontFamily = "verdana";
To style the (default white on black) element when the xycursor touches the X/Y axis (don't know what the correct name for this element is, hope you know which one I mean)
I would like to set the font size and family. Tried to set the color to red to see if it has to be set via the fill property, but also that doesn't work.
Created the cursor like this:
chart.cursor = new am4charts.XYCursor();
chart.cursor.xAxis = axis;
You have to set the tooltip properties inside the axis objects directly, as mentioned in the documentation. For example, to change the font, size and color in the category axis tooltip, modify the tooltip's label object:
categoryAxis.tooltip.getFillFromObject = false;
categoryAxis.tooltip.label.fill = "#ff0000"
categoryAxis.tooltip.label.fontFamily = "Courier New"
categoryAxis.tooltip.label.fontSize = 15;
Demo
I've implemented a QwtPlot which scrolls across the screen as data is added in real-time. Based on user input, an image of the plot is occasionally rendered to a file using QwtPlotRenderer. However, because the axis scrolls during normal operation, the QwtScaleDiv tick marks can look a little wonky at render time (they are right-aligned):
Is there some easy way in which I can recalculate the division prior to rendering so that the first label is on the far left and the last one is on the far right?
This isn't as difficult as it looked at first. Bascially, all you need to do is temporarily replace the axisScaleDiv.
auto divX = this->axisScaleDiv(xBottom);
double ub = divX.upperBound();
double lb = divX.lowerBound();
double numTicks = 11.0; // 10 even divisions
// you can create minor/medium ticks if you want to, I didn't.
QList<double> majorTicks;
for (int i = 0; i < numTicks; ++i)
{
majorTicks.push_back(lb + i * ((ub - lb) / (numTicks - 1)));
}
// set the scale to the newly created division
QwtScaleDiv renderDivX(divX.lowerBound(), divX.upperBound(),
QList<double>(), QList<double>(), majorTicks);
this->setAxisScaleDiv(xBottom, renderDivX);
// DO PLOT RENDERING
QwtPlotRender renderer;
renderer.renderDocument(...);
// RESOTRE PREVIOUS STATE
this->setAxisScaleDiv(xBottom, divX);
this->setAxisScaleDiv(yLeft, divY);
// update the axes
this->updateAxes();
I got some values that i need to draw as a vertical line. The line should be from begin till the end of diagramm field.
I use VCLTee.Chart.hpp in Embarcadero. As I know it is the Tchart, that is actually used more for Delphi.
However:
I use this function:
DlgMainWindow->ChartTemperatureCurve->Canvas->DoVertLine(XValue,YValue,ZValue);
i can´t find the description. As I see DoVertLine works with Pixel of the diagramm. But if my YValue = 10 , and should be always parallel to x for whole distance.
You should convert your YValue from axis values to pixels with the axis CalcPosValue function.
If you want to draw a line at a constant YValue, it would be an horizontal line, not a vertical line.
In the following example I'm drawing an horizontal line at YValue=10.
Note the drawing functions should be called at OnAfterDraw event or similar to make sure your custom drawings are done after every repaint.
To use OnAfterDraw event on RAD Studio, select the chart at design-time, navigate to the Events tab at the Object Inspector and double-click on the white cell next to OnAfterDraw.
This action should open the code view with the cursor inside a new and empty OnAfterDraw function.
Then you can add what you want to do there. Ie, drawing an horizontal line within the ChartRect, at YValue=10:
void __fastcall TForm1::Chart1AfterDraw(TObject *Sender)
{
Chart1->Canvas->Pen->Color = clRed;
int X0Pos = Chart1->ChartRect.Left;
int X1Pos = X0Pos + Chart1->ChartRect.Width();
double YVal = 10;
int YPos = Chart1->Axes->Left->CalcPosValue(YVal);
Chart1->Canvas->DoHorizLine(X0Pos, X1Pos, YPos);
}
So I am trying to create a mini-map/PIP. I have an existing program with scene that runs inside a Qt Widget. I have a class, NetworkViewer, which extends CompositeViewer. In NetworkViewer's constructor I call the following function. Notice the root is the scene which is populated elsewhere.
void NetworkViewer::init() {
root = new osg::Group() ;
viewer = new osgViewer::View( );
viewer->setSceneData( root ) ;
osg::Camera* camera ;
camera = createCamera(0,0,100,100) ;
viewer->setCamera( camera );
viewer->addEventHandler( new NetworkGUIHandler( (GUI*)view ) ) ;
viewer->setCameraManipulator(new osgGA::TrackballManipulator) ;
viewer->getCamera()->setClearColor(
osg::Vec4( LIGHT_CLOUD_BLUE_F,0.0f));
addView( viewer );
osgQt::GraphicsWindowQt* gw =
dynamic_cast( camera->getGraphicsContext() );
QWidget* widget = gw ? gw->getGLWidget() : NULL;
QGridLayout* grid = new QGridLayout( ) ;
grid->addWidget( widget );
grid->setSpacing(1);
grid->setMargin(1);
setLayout( grid );
initHUD( ) ;
}
The create camera function is as follows:
osg::Camera* createCamera( int x, int y, int w, int h ) {
osg::DisplaySettings* ds = osg::DisplaySettings::instance().get();
osg::ref_ptr traits
= new osg::GraphicsContext::Traits;
traits->windowName = "" ;
traits->windowDecoration = false ;
traits->x = x;
traits->y = y;
traits->width = w;
traits->height = h;
traits->doubleBuffer = true;
traits->alpha = ds->getMinimumNumAlphaBits();
traits->stencil = ds->getMinimumNumStencilBits();
traits->sampleBuffers = ds->getMultiSamples();
traits->samples = ds->getNumMultiSamples();
osg::ref_ptr camera = new osg::Camera;
camera->setGraphicsContext( new osgQt::GraphicsWindowQt(traits.get()) );
camera->setViewport( new osg::Viewport(0, 0, traits->width, traits->height) );
camera->setViewMatrix(osg::Matrix::translate(-10.0f,-10.0f,-30.0f));
camera->setProjectionMatrixAsPerspective(
20.0f,
static_cast(traits->width)/static_cast(traits->height),
1.0f, 10000.0f );
return camera.release();
}
I have been looking at several camera examples and searching for a solution for a while to no avail. What I am really looking for is the background being my main camera which takes up most of the screen and displays the scene graph while my mini-map appears in the bottom right. It has the same scene as the main camera but is overlaid on top of it and has its own set of controls for selection etc since it will have different functionality.
I was thinking that perhaps by adding another camera as a slave I would be able to do this:
camera = createCamera(40,40,50,50) ;
viewer->addSlave(camera) ;
But this doesn't seem to work. If I disable the other camera I do see a clear area that it appears this camera was suppose to be rendering in (its viewport) but that doesn't help. I've played around with rendering order thinking it could be that to no avail.
Any ideas? What it the best way to do such a minimap is? What am I doing wrong? Also anyway to make the rendering of the minimap circular instead of rectangular?
I am not personnally using OpenSceneGraph, so I can't advise you on your code. I think the best is to ask in the official forums. But I have some ideas on the minimap:
First, you have to specify the basic features of your minimap. Do you want it to emphasize some elements of the scene, or just show the scene (ie, RTS-like minimap vs simple top-show of the scene) ?
I assume you do not want to emphasize some elements of the scene. I also assume your main camera is not really 'minimap-friendly'. So, the simplest is to create a camera with the following properties:
direction = (0,-1,0) (Y is the vertical axis)
mode = orthographic
position = controlled by what you want, for example your main camera
Now, for the integration of the image. You can:
set the viewport of the minimap camera to what you want, if your minimap is rectangular.
render the minimap to a texture (RTT) and then blend it through an extra rendering pass.
You can also search other engines forums (like Irrlicht and Ogre) to see how they're doing minimaps.