export rendered tikz as png

misc0110 · misc0110 · commit e3f62a989525 · 2020-11-20T23:29:15.000+01:00
diff --git a/data/templates/template_beamer.pgs b/data/templates/template_beamer.pgs
@@ -1,4 +1,5 @@
 \documentclass{beamer}
+\beamertemplatenavigationsymbolsempty
 \usepackage{tikz}
 \usepackage{color}
 \usepackage{amssymb}
diff --git a/mainwindow.cpp b/mainwindow.cpp
@@ -63,6 +63,49 @@ void MainWindow::gotoPreviousImage() {
   }
 }
 
+
+bool MainWindow::isEmptyLine(QImage& img, int line) {
+    QColor white(255, 255, 255, 255);
+    for(int x = 0; x < img.width(); x++) {
+        if(img.pixelColor(x, line) != white) {
+            return false;
+        }
+    }
+    return true;
+}
+
+bool MainWindow::isEmptyCol(QImage& img, int col) {
+    QColor white(255, 255, 255, 255);
+    for(int y = 0; y < img.height(); y++) {
+        if(img.pixelColor(col, y) != white) {
+            return false;
+        }
+    }
+    return true;
+}
+
+void MainWindow::exportPNG() {
+    int top = 0;
+    while(isEmptyLine(image, top) && top < image.height() - 1) top++;
+    if(top > 0) top--;
+    int bottom = image.height() - 1;
+    while(isEmptyLine(image, bottom) && bottom > 0) bottom--;
+    if(bottom < image.height() - 1) bottom++;
+    int left = 0;
+    while(isEmptyCol(image, left) && left < image.width() - 1) left++;
+    if(left > 0) left--;
+    int right = image.width() - 1;
+    while(isEmptyCol(image, right) && right > 0) right--; 
+    if(right < image.width() - 1) right++;
+    
+    QImage crop;
+    crop = image.copy(left, top, right - left + 1, bottom - top + 1); 
+    QString fname = QFileDialog::getSaveFileUrl().toLocalFile();
+    std::cout << "Export as " << fname.toStdString() << std::endl;
+    crop.save(fname, "png", -1);
+
+}
+
 void MainWindow::render(double scale) {
   if (currentDoc && display) {
     if(currentPage >= currentDoc->numPages()) {
@@ -74,8 +117,9 @@ void MainWindow::render(double scale) {
     prevImage->setVisible(currentDoc->numPages() > 1);
     nextImage->setVisible(currentDoc->numPages() > 1);
     
-    QImage image = currentDoc->page(currentPage)->renderToImage(scale * physicalDpiX(), scale * physicalDpiY());
+    image = currentDoc->page(currentPage)->renderToImage(scale * physicalDpiX(), scale * physicalDpiY());
     display->setImage(image);
+ 
   }
 }
 
@@ -284,6 +328,7 @@ MainWindow::MainWindow() : currentDoc(NULL), renderProcess(NULL), currentPage(0)
   
   connect(prevImage, SIGNAL(triggered()), this, SLOT(gotoPreviousImage()));
   connect(nextImage, SIGNAL(triggered()), this, SLOT(gotoNextImage()));
+  connect(exportImgPng, SIGNAL(triggered()), this, SLOT(exportPNG()));
 
   connect((QObject *)doc, SIGNAL(textChanged(KTextEditor::Document *)), this,
           SLOT(textChanged(KTextEditor::Document *)));
@@ -427,6 +472,8 @@ void MainWindow::setupUI() {
   setupGUI(ToolBar | Keys | StatusBar | Save);
   createGUI(katePart);
   
+  exportImgPng = toolBar()->addAction(QIcon::fromTheme("image"), "Save as PNG");
+  
   toolBar()->addSeparator();
   prevImage = toolBar()->addAction(QIcon::fromTheme("go-previous"), "Previous image");
   nextImage = toolBar()->addAction(QIcon::fromTheme("go-next"), "Next image");
diff --git a/mainwindow.h b/mainwindow.h
@@ -54,6 +54,7 @@ public slots:
   void gotoPreviousImage();
   void gotoNextImage();
   void updateTemplate(const QString& filename);
+  void exportPNG();
 
 private:
   void setupActions();
@@ -68,7 +69,11 @@ public slots:
   void appendLog(QString str);
   
   void updateRootDirectory();
+  
+  bool isEmptyLine(QImage& img, int line);
+  bool isEmptyCol(QImage& img, int col);
 
+  QImage image;
   QWidget *window;
   QSplitter *splitView;
   QHBoxLayout *mainLayout;
@@ -112,6 +117,7 @@ public slots:
   
   QAction* nextImage;
   QAction* prevImage;
+  QAction* exportImgPng;
   
   int currentPage;
   bool usersaved;

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,5 @@`
`1`	`1`	`\documentclass{beamer}`
	`2`	`+\beamertemplatenavigationsymbolsempty`
`2`	`3`	`\usepackage{tikz}`
`3`	`4`	`\usepackage{color}`
`4`	`5`	`\usepackage{amssymb}`