add example for pointilistic image plot, using a scatter plot

JKQtPlotterBuildAllExamples.pro

@@ -51,6 +51,7 @@ addSimpleTest(speed)
 addSimpleTest(rgbimageplot_qt)
 addSimpleTest(impulsesplot)
 addSimpleTest(paramscatterplot)
+addSimpleTest(paramscatterplot_image)
 addSimpleTest(parametriccurve)
 addSimpleTest(parsedfunctionplot)
 addSimpleTest(functionplot)

README.md

@@ -32,6 +32,7 @@ All test-projects are Qt-projects that use qmake to build. You can load them int
 | [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_filledgraphs_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/simpletest_filledgraphs) | [Filled Curve Plots](https://github.com/jkriege2/JKQtPlotter/tree/master/test/simpletest_filledgraphs) | `JKQTPbarVerticalGraph`<br/>setting/altering data in `JKQTPdatstore` directly<br/> transparent plots<br/>calculating histograms |
 | [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_impulsesplot_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/simpletest_impulsesplot) | [Impulse Plots](https://github.com/jkriege2/JKQtPlotter/tree/master/test/simpletest_impulsesplot) | `JKQTPimpulsesVerticalGraph` and `JKQTPimpulsesHorizontalGraph`<br/>C++-style QVector as plot data |
 | [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_paramscatterplot_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/simpletest_paramscatterplot) | [Scatter Graph with Parametrized Symbols/Colors](https://github.com/jkriege2/JKQtPlotter/tree/master/test/simpletest_paramscatterplot) | `JKQTPxyParametrizedScatterGraph`<br/>C++-style QVector as plot data<br/>modify scatter/points/line-graph properties by data |
+| [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_paramscatterplot_image_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/simpletest_paramscatterplot_image) | [Draw an Artistic Image with a Parametrized Scatter Graph](https://github.com/jkriege2/JKQtPlotter/tree/master/test/simpletest_paramscatterplot_image) | `JKQTPxyParametrizedScatterGraph`<br/>C++-style QVector as plot data<br/>rectangular arrangement of scatters<br/>generative computer graphics |
 | [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_parametriccurve_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/simpletest_parametriccurve) | [Plotting Parametric Curves](https://github.com/jkriege2/JKQtPlotter/tree/master/test/simpletest_parametriccurve) | `JKQTPxyLineGraph` and `JKQTPxyParametrizedScatterGraph`<br/>C++-style QVector as plot data<br/>parametric curve plotting |
 | [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_functionplot_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/simpletest_functionplot) | [Plotting Mathematical Functions as Line Graphs](https://github.com/jkriege2/JKQtPlotter/tree/master/test/simpletest_functionplot) | `JKQTPxFunctionLineGraph` <br/>diretly plotting C/C++-functions |
 [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_parsedfunctionplot_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/simpletest_parsedfunctionplot) | [Plotting Parsed Mathematical Functions as Line Graphs](https://github.com/jkriege2/JKQtPlotter/tree/master/test/simpletest_parsedfunctionplot) | `JKQTPxParsedFunctionLineGraph` <br/>plotting functions with the internal math equation parser/evaluator |

lib/jkqtplotter/jkqtpgraphs.h

@@ -198,13 +198,13 @@ class LIB_EXPORT JKQTPxyParametrizedScatterGraph: public JKQTPxyLineGraph, publi
         /** \brief this column contains the line width */
         int linewidthColumn;
 
-        /** \brief if the gridModeForSymbolSize mode is actiavted (false), the plot assumes that the scatter symbols are ordered in a grid. It the uses the given griDeltaX and gridDeltaY to calculate the symbol size, so they fill the available space to a fraction gridSymbolFractionSize. */
+        /** \brief if the gridModeForSymbolSize mode is actiavted (true), the plot assumes that the scatter symbols are ordered in a grid. It the uses the given griDeltaX and gridDeltaY to calculate the symbol size, so they fill the available space to a fraction gridSymbolFractionSize. */
         bool gridModeForSymbolSize;
-        /** \brief if the gridModeForSymbolSize mode is actiavted (false), the plot assumes that the scatter symbols are ordered in a grid. It the uses the given griDeltaX and gridDeltaY to calculate the symbol size, so they fill the available space to a fraction gridSymbolFractionSize. */
+        /** \brief if the gridModeForSymbolSize mode is actiavted (true), the plot assumes that the scatter symbols are ordered in a grid. It the uses the given griDeltaX and gridDeltaY to calculate the symbol size, so they fill the available space to a fraction gridSymbolFractionSize. */
         double gridDeltaX;
-        /** \brief if the gridModeForSymbolSize mode is actiavted (false), the plot assumes that the scatter symbols are ordered in a grid. It the uses the given griDeltaX and gridDeltaY to calculate the symbol size, so they fill the available space to a fraction gridSymbolFractionSize. */
+        /** \brief if the gridModeForSymbolSize mode is actiavted (true), the plot assumes that the scatter symbols are ordered in a grid. It the uses the given griDeltaX and gridDeltaY to calculate the symbol size, so they fill the available space to a fraction gridSymbolFractionSize. */
         double gridDeltaY;
-        /** \brief if the gridModeForSymbolSize mode is actiavted (false), the plot assumes that the scatter symbols are ordered in a grid. It the uses the given griDeltaX and gridDeltaY to calculate the symbol size, so they fill the available space to a fraction gridSymbolFractionSize. */
+        /** \brief if the gridModeForSymbolSize mode is actiavted (true), the plot assumes that the scatter symbols are ordered in a grid. It the uses the given griDeltaX and gridDeltaY to calculate the symbol size, so they fill the available space to a fraction gridSymbolFractionSize. */
         double gridSymbolFractionSize;
 
         /** \brief if this is true, the value in the colorColumn is converted to an integer, representing a color in ARGB format (as in QRgb) */

test/simpletest_paramscatterplot_image/README.md

@@ -0,0 +1,99 @@
+[Back to JKQTPlotter main page](https://github.com/jkriege2/JKQtPlotter/)
+
+# JKQtPlotter
+
+## Draw an Artistic Image with a Parametrized Scatter Graph
+This project (see `./test/simpletest_paramscatterplot_image/`) demonstrates the capabilities of `JKQTPxyParametrizedScatterGraph` to display parametrized scatters in a rectangular arrangement. See the test program in [`test/simpletest_paramscatterplot`](https://github.com/jkriege2/JKQtPlotter/blob/master/test/simpletest_paramscatterplot) for a basic example of the capabilities of `JKQTPxyParametrizedScatterGraph`.
+
+In this example, we load an image, convert it to greyscale and store it, together with x/y-coordinate-vectors in the datastore. Then a `JKQTPxyParametrizedScatterGraph` is used to draw the image as a pointilistic artwork, where each pixel is represented by a disk. The color of the disk is chosen from a color-palette, based on the grey-value. The size of each disk is chosen from the inverse grey value.
+
+First we prepare the data, as described above. The image is loaded and then converted to the required data vectors.
+```c++
+    // 2.1 load image
+    QImage image(":/example.bmp");
+    QVector<double> imageVector, pointSizes;
+    QVector<double> X,Y;
+
+    // 2.2 convert image to greyscale, stored in a vector in row-major order
+    double maxSymbolSize=30; // maximal diameter of symbols in pt
+    for (int y=0; y<image.height(); y++) {
+        for (int x=0; x<image.width(); x++) {
+            // calculate grey-value image vector
+            imageVector.push_back(qGray(image.pixel(x,y)));
+            // calculate point sizes from inverse grey value and scaling between 0 and maxSymbolSize
+            pointSizes.push_back(static_cast<double>(255-qGray(image.pixel(x,y)))/255.0*maxSymbolSize);
+            // calculate X/Y-coordinates (y mirrored, so image is upright)
+            X.push_back(x);
+            Y.push_back(image.height()-1-y);
+        }
+    }
+
+    // 2.3 and copy it to the datastore
+    size_t columnX=ds->addCopiedColumn(X, "x");
+    size_t columnY=ds->addCopiedColumn(Y, "y");
+    size_t columnG=ds->addCopiedColumn(imageVector, "greyscaleImageData");
+    size_t columnS=ds->addCopiedColumn(pointSizes, "pointSizes");
+```
+
+Now we can use th datavectors to add a `JKQTPxyParametrizedScatterGraph`:
+```c++
+    JKQTPxyParametrizedScatterGraph* graph1=new JKQTPxyParametrizedScatterGraph(&plot);
+    graph1->set_xColumn(columnX);
+    graph1->set_yColumn(columnY);
+    graph1->set_sizeColumn(columnS);
+    graph1->set_symbol(JKQTPfilledCircle);
+    graph1->set_colorColumn(columnG);
+    graph1->set_palette(JKQTPMathImageMATLAB);
+    graph1->set_drawLine(false);
+    graph1->set_title("");
+    plot.addGraph(graph1);
+```
+
+For illustrative purposes, the original image is shown at the bottom-left:
+```c++
+    JKQTPImage* graph2=new JKQTPImage(&plot);
+    graph2->set_image(image);
+    graph2->set_x(0);
+    graph2->set_y(0);
+    graph2->set_width(10);
+    graph2->set_height(10);
+    plot.addGraph(graph2);
+```
+
+Finally the plot is styled and the axis aspect ratios are fixed:
+```c++
+    // scale the plot so the graph is contained and format the coordinate system
+    plot.getXAxis()->set_axisLabel("x-axis");
+    plot.getYAxis()->set_axisLabel("y-axis");
+    plot.getXAxis()->set_drawGrid(false);
+    plot.getYAxis()->set_drawGrid(false);
+    // max. size is the size of the image
+    plot.setXY(0,image.width()-1,0,image.height()-1);
+    plot.setAbsoluteXY(0,image.width()-1,0,image.height()-1);
+    // ensure that axis aspect ration and coordinate system aspect ratio are maintained
+    plot.get_plotter()->set_maintainAspectRatio(true);
+    plot.get_plotter()->set_aspectRatio(1);
+    plot.get_plotter()->set_maintainAxisAspectRatio(true);
+    plot.get_plotter()->set_axisAspectRatio(1);
+```
+
+The full test appication combines all these variants and the result looks like this:
+
+![jkqtplotter_simpletest_paramscatterplot_image](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_paramscatterplot_image.png)
+
+You can modify the example above in several ways, e.g. by choosing another symbol (e.g. a star):
+
+![jkqtplotter_simpletest_paramscatterplot_image_star](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_paramscatterplot_image_star.png)
+
+... or by changing the color palette and the symbol:
+
+![jkqtplotter_simpletest_paramscatterplot_image_palette](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_paramscatterplot_image_palette.png)
+
+![jkqtplotter_simpletest_paramscatterplot_image_palette_triangle](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_paramscatterplot_image_palette_triangle.png)
+
+... or even  to set a different symbol for each pixel, based on the values in `columnS` (simply add `graph1->set_symbolColumn(columnS)`):
+
+
+![jkqtplotter_simpletest_paramscatterplot_image_varsymbol](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_paramscatterplot_image_varsymbol.png)
+
+[Back to JKQTPlotter main page](https://github.com/jkriege2/JKQtPlotter/)

test/simpletest_paramscatterplot_image/jkqtplotter_simpletest_paramscatterplot_image.cpp

@@ -0,0 +1,86 @@
+#include <QApplication>
+#include "jkqtplotter/jkqtplotter.h"
+#include "jkqtplotter/jkqtpgraphs.h"
+#include "jkqtplotter/jkqtpgraphsimage.h"
+
+
+int main(int argc, char* argv[])
+{
+    QApplication app(argc, argv);
+
+    // 1. create a plotter window and get a pointer to the internal datastore (for convenience)
+    JKQtPlotter plot;
+    JKQTPdatastore* ds=plot.getDatastore();
+
+    // 2. Prepare Data
+    // 2.1 load image
+    QImage image(":/example.bmp");
+    QVector<double> imageVector, pointSizes;
+    QVector<double> X,Y;
+
+    // 2.2 convert image to greyscale, stored in a vector in row-major order
+    double maxSymbolSize=30; // maximal diameter of symbols in pt
+    for (int y=0; y<image.height(); y++) {
+        for (int x=0; x<image.width(); x++) {
+            // calculate grey-value image vector
+            imageVector.push_back(qGray(image.pixel(x,y)));
+            // calculate point sizes from inverse grey value and scaling between 0 and maxSymbolSize
+            pointSizes.push_back(static_cast<double>(255-qGray(image.pixel(x,y)))/255.0*maxSymbolSize);
+            // calculate X/Y-coordinates (y mirrored, so image is upright)
+            X.push_back(x);
+            Y.push_back(image.height()-1-y);
+        }
+    }
+
+    // 2.3 and copy it to the datastore
+    size_t columnX=ds->addCopiedColumn(X, "x");
+    size_t columnY=ds->addCopiedColumn(Y, "y");
+    size_t columnG=ds->addCopiedColumn(imageVector, "greyscaleImageData");
+    size_t columnS=ds->addCopiedColumn(pointSizes, "pointSizes");
+
+    // 3. add graphs to plot
+    // 3.1 Now add a parametrized scatter graph with columnX, columnY for the positions of the
+    //     scatter points, where the symbol size is given by column columnS and the color of
+    //     each symbol is set from column columnG, via a color palette JKQTPMathImageMATLAB
+    JKQTPxyParametrizedScatterGraph* graph1=new JKQTPxyParametrizedScatterGraph(&plot);
+    graph1->set_xColumn(columnX);
+    graph1->set_yColumn(columnY);
+    graph1->set_sizeColumn(columnS);
+    graph1->set_symbolColumn(columnS);
+    graph1->set_symbol(JKQTPfilledTriangle);
+    graph1->set_colorColumn(columnG);
+    graph1->set_palette(JKQTPMathImageOCEAN);
+    graph1->set_drawLine(false);
+    graph1->set_title("");
+    plot.addGraph(graph1);
+
+    // 3.2 add an image to display the original graphics
+    JKQTPImage* graph2=new JKQTPImage(&plot);
+    graph2->set_image(image);
+    graph2->set_x(0);
+    graph2->set_y(0);
+    graph2->set_width(10);
+    graph2->set_height(10);
+    plot.addGraph(graph2);
+
+
+    // 4. scale the plot so the graph is contained and format the coordinate system
+    plot.getXAxis()->set_axisLabel("x-axis");
+    plot.getYAxis()->set_axisLabel("y-axis");
+    plot.getXAxis()->set_drawGrid(false);
+    plot.getYAxis()->set_drawGrid(false);
+    // max. size is the size of the image
+    plot.setXY(0,image.width()-1,0,image.height()-1);
+    plot.setAbsoluteXY(0,image.width()-1,0,image.height()-1);
+    // ensure that axis aspect ration and coordinate system aspect ratio are maintained
+    plot.get_plotter()->set_maintainAspectRatio(true);
+    plot.get_plotter()->set_aspectRatio(1);
+    plot.get_plotter()->set_maintainAxisAspectRatio(true);
+    plot.get_plotter()->set_axisAspectRatio(1);
+
+    // 5. show plotter and make it a decent size
+    plot.show();
+    plot.resize(800,800);
+
+    return app.exec();
+}

test/simpletest_paramscatterplot_image/jkqtplotter_simpletest_paramscatterplot_image.pro

@@ -0,0 +1,25 @@
+# source code for this simple demo
+SOURCES = jkqtplotter_simpletest_paramscatterplot_image.cpp 
+
+RESOURCES += jkqtplotter_simpletest_paramscatterplot_image.qrc
+
+# configure Qt
+CONFIG += qt
+QT += core gui xml  svg
+greaterThan(QT_MAJOR_VERSION, 4): QT += widgets printsupport
+
+# output executable name
+TARGET = jkqtplotter_simpletest_paramscatterplot_image
+
+
+# include JKQtPlotter source code
+DEPENDPATH += . ../../lib
+INCLUDEPATH += ../../lib
+CONFIG (debug, debug|release):LIBS += -L../../lib/debug -ljkqtplotterlib
+CONFIG (release):LIBS += -L../../lib/release -ljkqtplotterlib
+
+win32-msvc*: DEFINES += _USE_MATH_DEFINES
+
+# here you can activate some debug options
+#DEFINES += SHOW_JKQTPLOTTER_DEBUG
+#DEFINES += JKQTBP_AUTOTIMER

test/simpletest_paramscatterplot_image/jkqtplotter_simpletest_paramscatterplot_image.qrc

@@ -0,0 +1,5 @@
+<RCC>
+    <qresource prefix="/">
+        <file>example.bmp</file>
+    </qresource>
+</RCC>

test/simpletest_paramscatterplot_image/jkqtplotter_simpletest_paramscatterplot_image_and_lib.pro

@@ -0,0 +1,8 @@
+TEMPLATE = subdirs
+
+SUBDIRS +=  jkqtplotterlib jkqtplotter_simpletest_paramscatterplot_image
+
+jkqtplotterlib.file = ../../lib/jkqtplotterlib.pro
+
+jkqtplotter_simpletest_paramscatterplot_image.file=$$PWD/jkqtplotter_simpletest_paramscatterplot_image.pro
+jkqtplotter_simpletest_paramscatterplot_image.depends = jkqtplotterlib