added simple JKQTmathText example

README.md

@@ -275,8 +275,75 @@ Scatter Plots can have symbols where the shape/color/size is parametrized by a d
 ![LogLog Plot](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/screen_parmetrizedplots_datatable.png)
 
 
+
+
 #JKQTmathText
 JKQTmathText is a hand-written LaTeX-renderer for Qt (implemented in native C++, using Qt). It supports a large set of standard LaTeX markup and can render it to a QPainter.
+##A simple usage example
+This project (see `./test/jkqtmathtext_simpletest/`) simply creates a QLabel (as a new window) that displays a rendered LaTeX equation (here the time-dependent Schrödinger equation).
+The QMake project looks like this (see `./test/jkqtmathtext_simpletest/jkqtmathtext_simpletest.pro`):
+```qmake
+# include JKQTmathText source-code, including the open-source XITS fonts
+include(../../jkqtmathtext_with_xits.pri)
+SOURCES += jkqtmathtext_simpletest.cpp
+
+# if you don't want to use the XITS fonts, use this line (and uncomment the 
+# last two line!):
+#include(../../jkqtmathtext.pri)
+
+CONFIG += qt
+QT += core gui
+greaterThan(QT_MAJOR_VERSION, 4): QT += widgets printsupport
+
+TARGET = jkqtmathtext_simpletest
+```
+And the soruce code of the main application is (see `./test/jkqtmathtext_simpletest/jkqtmathtext_simpletest.cpp`):
+```c++
+#include <QApplication>
+#include <QLabel>
+#include <QPixmap>
+#include "jkqtmathtext.h"
+
+int main(int argc, char* argv[])
+{
+    QApplication app(argc, argv);
+
+    // we use a simple label to display the math text
+    QLabel lab;
+
+    // 1. we will paint into a QPixmap
+    QPixmap pix(600,400);
+    pix.fill(QColor("white"));
+    QPainter painter;
+
+    // 2. now we create a JKQTmathText object.
+    //    Also we configure the JKQTmathText to use the XITS fonts that
+    //    were included in the *.pro-file
+    JKQTmathText mathText;
+    mathText.useXITS();
+    mathText.set_fontSize(20);
+
+    // 3. now we parse some LaTeX code (the Schroedinger's equation), so
+    //    we can draw it onto the QPixmap in the next step
+    mathText.parse("$\\left[-\\frac{\\hbar^2}{2m}\\frac{\\partial^2}{\\partial x^2}+V(x)\\right]\\Psi(x)=\\mathrm{i}\\hbar\\frac{\\partial}{\\partial t}\\Psi(x)$");
+
+    // 3. here we do the painting
+    painter.begin(&pix);
+    mathText.draw(painter, Qt::AlignCenter, QRectF(0,0,pix.width(), pix.height()), false);
+    painter.end();
+
+    // now we display and resize the label as a window
+    lab.setPixmap(pix);
+    lab.show();
+    lab.resize(600,400);
+
+    return app.exec();
+}
+```
+The result looks like this:
+![jkqtmathtext_simpletest](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtmathtext_simpletest.png)
+
+##Screenshots
 ![LatexRender](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/mscreen_schroedinger.png)
 ![LatexRender](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/mscreen_rottaion.png)
 ![LatexRender](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/mscreen_maxwell.png)

test/jkqtmathtext_simpletest/jkqtmathtext_simpletest.cpp

@@ -0,0 +1,40 @@
+#include <QApplication>
+#include <QLabel>
+#include <QPixmap>
+#include "jkqtmathtext.h"
+
+int main(int argc, char* argv[])
+{
+    QApplication app(argc, argv);
+
+    // we use a simple label to display the math text
+    QLabel lab;
+
+    // 1. we will paint into a QPixmap
+    QPixmap pix(600,400);
+    pix.fill(QColor("white"));
+    QPainter painter;
+
+    // 2. now we create a JKQTmathText object.
+    //    Also we configure the JKQTmathText to use the XITS fonts that
+    //    were included in the *.pro-file
+    JKQTmathText mathText;
+    mathText.useXITS();
+    mathText.set_fontSize(20);
+
+    // 3. now we parse some LaTeX code (the Schroedinger's equation), so
+    //    we can draw it onto the QPixmap in the next step
+    mathText.parse("$\\left[-\\frac{\\hbar^2}{2m}\\frac{\\partial^2}{\\partial x^2}+V(x)\\right]\\Psi(x)=\\mathrm{i}\\hbar\\frac{\\partial}{\\partial t}\\Psi(x)$");
+
+    // 3. here we do the painting
+    painter.begin(&pix);
+    mathText.draw(painter, Qt::AlignCenter, QRectF(0,0,pix.width(), pix.height()), false);
+    painter.end();
+
+    // now we display and resize the label as a window
+    lab.setPixmap(pix);
+    lab.show();
+    lab.resize(600,400);
+
+    return app.exec();
+}

test/jkqtmathtext_simpletest/jkqtmathtext_simpletest.pro

@@ -0,0 +1,10 @@
+include(../../jkqtmathtext_with_xits.pri)
+SOURCES += jkqtmathtext_simpletest.cpp
+
+CONFIG += qt
+QT += core gui
+greaterThan(QT_MAJOR_VERSION, 4): QT += widgets printsupport
+
+TARGET = jkqtmathtext_simpletest
+
+

test/jkqtmathtext_test/testform.cpp

@@ -107,7 +107,7 @@ TestForm::TestForm(QWidget *parent) :
     ui->cmbTestset->addItem("lim, sum ...", "$\\lim_{x\\to\\infty} f(x) = \\binom{k}{r} + \\frac{a}{b} \\sum_{n=1}^\\infty a_n + \\displaystyle{ \\left\\{ \\frac{1}{13} \\sum_{n=1}^\\infty b_n \\right\\} }.$");
     ui->cmbTestset->addItem("array test", "$f(x) := \\left\\{\\begin{array} x^2 \\sin \\frac{1}{x} & \\textrm{if } x \\ne 0, \\\\ 0 & \\textrm{if } x = 0 . \\end{array}\\right.$");
     ui->cmbTestset->addItem("Schwinger-Dyson", "$\\left\\langle\\psi\\left|\\mathcal{T}\\{F \\phi^j\\}\\right|\\psi\\right\\rangle=\\left\\langle\\psi\\left|\\mathcal{T}\\{iF_{,i}D^{ij}-FS_{int,i}D^{ij}\\}\\right|\\psi\\right\\rangle.$");
-    ui->cmbTestset->addItem(QLatin1String("Schrödinger's equation"), "$\\left[-\\frac{\\hbar^2}{-2m}\\frac{\\partial^2}{\\partial x^2}+V\\right]\\Psi(x)=i\\hbar\\frac{\\partial}{\\partial t}\\Psi(x)$");
+    ui->cmbTestset->addItem(QLatin1String("Schrödinger's equation"), "$\\left[-\\frac{\\hbar^2}{2m}\\frac{\\partial^2}{\\partial x^2}+V\\right]\\Psi(x)=\\mathrm{i}\\hbar\\frac{\\partial}{\\partial t}\\Psi(x)$");
     ui->cmbTestset->addItem("Cauchy-Schwarz inequality", "$\\left( \\sum_{k=1}^n a_k b_k \\right)^2 \\leq \\left( \\sum_{k=1}^n a_k^2 \\right) \\left( \\sum_{k=1}^n b_k^2 \\right)$");
     ui->cmbTestset->addItem("Maxwell's equations", "$\\begin{aligned}\\nabla \\times \\vec{\\mathbf{B}} -\\, \\frac{1}{c}\\, \\frac{\\partial\\vec{\\mathbf{E}}}{\\partial t} & = \\frac{4\\pi}{c}\\vec{\\mathbf{j}} \\\\   \\nabla \\cdot \\vec{\\mathbf{E}} & = 4 \\pi \\rho \\\\\\nabla \\times \\vec{\\mathbf{E}}\\, +\\, \\frac{1}{c}\\, \\frac{\\partial\\vec{\\mathbf{B}}}{\\partial t} & = \\vec{\\mathbf{0}} \\\\\\nabla \\cdot \\vec{\\mathbf{B}} & = 0 \\end{aligned}$");
     //ui->cmbTestset->addItem("", "$$");