improved high-dpr-support in JKQTMathText

doc/dox/whatsnew.dox

@@ -17,6 +17,7 @@ Changes, compared to  \ref page_whatsnew_V4_0_0 "v4.0.0" include:
   <li>fixed issue described in <a href="https://github.com/jkriege2/JKQtPlotter/pull/62">#62: Fix custom labels draw, because giving exactly two label-strings did not display all of them</a>, thanks to <a href="https://github.com/FalsinSoft">user:FalsinSoft</a></li>
   <li>fixed issue <a href="https://github.com/jkriege2/JKQtPlotter/pull/70">#70: Typo in jkqtplotter/CMakeLists.txt</a>, thanks to <a href="https://github.com/tedlinlab">user:tedlinlab</a></li>
   <li>fixed: styling was not properly applied to coordinate axes of colorbars outside the plot</li>
+  <li>improved: high-dpr-support in JKQTMathText</li>
   <li>NEW: JKQTPFilledCurveXGraph and JKQTPFilledCurveYGraph can now plot wiggle plots with different fill styles above and below the baseline (feature request <a href="https://github.com/jkriege2/JKQtPlotter/issues/68">#68 Wiggle Plots</a> from <a href="https://github.com/xichaoqiang">user:xichaoqiang</a>   </li>
   <li>NEW/BREAKING CHANGE: data tooltip can now also be shown when "just" moving the mouse (so far this was only possible when dragging the mouse with a button pressed). This also removes JKQtPlotter::getActMouseLeftAsToolTip() and adds JKQtPlotter::getActMouseMoveToolTip() instead! Also the default toolbars and context menus changed!</li>
   <li>NEW: new "seaborn" style for plots</li>

examples/jkqtmathtext_simpletest/jkqtmathtext_simpletest.cpp

@@ -23,7 +23,9 @@ int main(int argc, char* argv[])
     QLabel lab;
 
     // 1. we will paint into a QPixmap
-    QPixmap pix(600,400);
+    const qreal dpr = lab.devicePixelRatioF();
+    QPixmap pix(600*dpr,400*dpr);
+    pix.setDevicePixelRatio(dpr);
     pix.fill(QColor("white"));
     QPainter painter;
 
@@ -40,7 +42,7 @@ int main(int argc, char* argv[])
 
     // 3. here we do the painting
     painter.begin(&pix);
-    mathText.draw(painter, Qt::AlignCenter, QRectF(0,0,pix.width(), pix.height()), false);
+    mathText.draw(painter, Qt::TopLeftCorner, QRectF(0,0,pix.width(), pix.height()), false);
     painter.end();
 
     // now we display and resize the label as a window

examples/jkqtmathtext_test/testform.cpp

@@ -226,7 +226,7 @@ TestForm::~TestForm()
     delete ui;
 }
 
-#define W 2000
+#define W 3000
 #define H 2000
 #define X1 15
 #define Y1 50
@@ -390,8 +390,10 @@ void TestForm::updateMath()
 
     ui->scrollArea->setBackgroundRole(QPalette::Dark);
 
-    QPixmap pix(W, H);
+    const qreal dpr = devicePixelRatioF();
+    QPixmap pix(W*dpr, H*dpr);
     pix.fill();
+    pix.setDevicePixelRatio(dpr);
     QPainter painter;
     JKQTMathText mt(this);
 

lib/jkqtmathtext/jkqtmathtext.cpp

@@ -4780,8 +4780,11 @@ void JKQTMathTextLabel::internalPaint()
             if (!m_mathText->parse(lastText)) {
                 //qDebug()<<"JKQTMathTextLabel::internalPaint(): parse '"<<lastText<<"': "<<m_mathText->parse(lastText)<<"\n  "<<m_mathText->getErrorList().join("\n")<<"\n\n";
             }
-
+            if (buffer.width()<=0 || buffer.height()<=0) {
-            if (buffer.width()<=0 || buffer.height()<=0) buffer=QPixmap(1000,100);
+                const qreal dpr = devicePixelRatioF();
+                buffer=QPixmap(1000*dpr,100*dpr);
+                buffer.setDevicePixelRatio(dpr);
+            }
             //qDebug()<<"internalPaint(): buffer "<<buffer.size();
             QPainter p;
             //qDebug()<<"internalPaint(): "<<p.begin(&buffer);
@@ -4794,10 +4797,12 @@ void JKQTMathTextLabel::internalPaint()
             size=m_mathText->getSize(p);
             p.end();
         }
-        buffer=QPixmap(static_cast<int>(qMax(32.0,size.width()*1.2)), static_cast<int>(qMax(10.0,size.height()*1.1)));
+        const qreal dpr = devicePixelRatioF();
+        buffer=QPixmap(static_cast<int>(qMax(32.0,size.width()*1.2))*dpr, static_cast<int>(qMax(10.0,size.height()*1.1))*dpr);
+        buffer.setDevicePixelRatio(dpr);
         buffer.fill(Qt::transparent);
         {
-            //qDebug()<<"internalPaint(): "<<buffer.size()<<size;
+            qDebug()<<"internalPaint(): buffer.size()="<<buffer.size()<<" size="<<size<<" dpr="<<dpr;
             QPainter p;
             //qDebug()<<"internalPaint(): "<<p.begin(&buffer);
             p.begin(&buffer);
@@ -4818,14 +4823,7 @@ void JKQTMathTextLabel::internalPaint()
 
 void JKQTMathTextLabel::paintEvent(QPaintEvent *event)
 {
-    //QLabel::paintEvent(event);
-    //return;
-
-    //qDebug()<<"paintEvent: "<<buffer.size();
-
-    //QApplication::processEvents();
     QLabel::paintEvent(event);
-    //qDebug()<<"paintEvent DONE: "<<size();
 }