Implemented yAxis Header texture cache to save on font drawing

Graphs/gGraphView.cpp

@@ -1053,7 +1053,9 @@ gGraph::gGraph(gGraphView *graphview,QString title,QString units, int height,sho
     m_lastx23=0;
 
     titleImage=QImage();
-    invalidate_VertTextCache=true;
+    yAxisImage=QImage();
+    yAxisImageTex=titleImageTex=0;
+    invalidate_yAxisImage=true;
 
     m_quad=new gVertexBuffer(64,GL_QUADS);
     m_quad->forceAntiAlias(true);
@@ -1178,22 +1180,28 @@ void gGraph::paint(int originX, int originY, int width, int height)
         int title_x,yh;
         if (titleImage.isNull()) {
             // Render the title to a texture so we don't have to draw the vertical text every time..
-            GetTextExtent("Wy@",x,yh,mediumfont);
+
+            GetTextExtent("Wy@",x,yh,mediumfont); // This gets a better consistent height. should be cached.
+
             GetTextExtent(title(),x,y,mediumfont);
 
             y=yh;
             QPixmap tpm=QPixmap(x+4,y+4);
 
-            tpm.fill(Qt::transparent);
+            tpm.fill(Qt::transparent); //empty it
             QPainter pmp(&tpm);
 
-            QBrush brush2(Qt::black);
+            pmp.setRenderHint(QPainter::Antialiasing, true);
+
+            QBrush brush2(Qt::black); // text color
             pmp.setBrush(brush2);
 
             pmp.setFont(*mediumfont);
-            pmp.drawText(2,y,title());
+
+            pmp.drawText(2,y,title()); // draw from the bottom
             pmp.end();
 
+            // convert to QImage and bind to a texture for future use
             titleImage=QGLWidget::convertToGLFormat(tpm.toImage().mirrored(false,true));
             titleImageTex=m_graphview->bindTexture(titleImage);
         }
@@ -1207,17 +1215,18 @@ void gGraph::paint(int originX, int originY, int width, int height)
 
         glEnable(GL_TEXTURE_2D);
 
+        // Rotate and draw vertical texture containing graph titles
         glPushMatrix();
         glTranslatef(marginLeft()+4,originY+height/2+x/2, 0);
         glRotatef(-90,0,0,1);
         m_graphview->drawTexture(QPoint(0,y/2),titleImageTex);
-
         glPopMatrix();
 
-
         glDisable(GL_TEXTURE_2D);
         glDisable(GL_BLEND);
 
+        // All that to replace this little, but -hideously- slow line of text..
+
         //renderText(title(),marginLeft()+title_x,originY+height/2,90,Qt::black,mediumfont);
         left+=title_x;
     } else left=0;
@@ -1228,8 +1237,6 @@ void gGraph::paint(int originX, int originY, int width, int height)
     lines()->add(0,originY,0,originY+height,col);
     lines()->add(left,originY,left,originY+height,col);
 #endif
-
-
     int tmp;
 
     left=0;

Graphs/gGraphView.h

@@ -548,7 +548,7 @@ public:
     float height() { return m_height; }
 
     //! \brief Set the height element. (relative to the total of all heights)
-    void setHeight(float height) { m_height=height; invalidate_VertTextCache=true;}
+    void setHeight(float height) { m_height=height; invalidate_yAxisImage=true;}
 
     int minHeight() { return m_min_height; }
     void setMinHeight(int height) { m_min_height=height; }
@@ -728,13 +728,17 @@ public:
     Layer * getLineChart();
     QRect m_lastbounds;
     QTimer * timer;
-    QImage titleImage;
-    GLuint titleImageTex;
-    bool invalidate_VertTextCache;
+    QImage titleImage,yAxisImage;
+    GLuint titleImageTex,yAxisImageTex;
+
+
+    // This gets set to true to force a redraw of the yAxis tickers when graphs are resized.
+    bool invalidate_yAxisImage;
 
     //! \brief Returns a Vector reference containing all this graphs layers
     QVector<Layer *>  & layers() { return m_layers; }
 
+    gGraphView * graphView() { return m_graphview; }
     short m_marginleft, m_marginright, m_margintop, m_marginbottom;
 protected:
     //void invalidate();

Graphs/gYAxis.cpp

@@ -137,9 +137,20 @@ gYAxis::~gYAxis()
 }
 void gYAxis::paint(gGraph & w,int left,int top, int width, int height)
 {
+    // may as well draw a cached texture here, and only update it when screen or graph is resized.
+    int x,y,yh=0;
+
+    if (w.invalidate_yAxisImage) {
+
+        if (!w.yAxisImage.isNull()) {
+            w.graphView()->deleteTexture(w.yAxisImageTex);
+            w.yAxisImage=QImage();
+        }
+
+
         if (height<0) return;
         if (height>2000) return;
-    int x,y;
+
         int labelW=0;
 
         EventDataType miny=w.min_y;
@@ -152,9 +163,15 @@ void gYAxis::paint(gGraph & w,int left,int top, int width, int height)
         w.roundY(miny,maxy);
 
         EventDataType dy=maxy-miny;
-
         static QString fd="0";
         GetTextExtent(fd,x,y);
+        yh=y;
+
+        QPixmap pixmap(width,height+y+4);
+
+        pixmap.fill(Qt::transparent);
+        QPainter paint(&pixmap);
+
 
         double max_yticks=round(height / (y+14.0)); // plus spacing between lines
 
@@ -182,13 +199,6 @@ void gYAxis::paint(gGraph & w,int left,int top, int width, int height)
 
         double min_ytick=rxy*yt;
 
-
-    //if (dy>5) {
-    //    min_ytick=round(min_ytick);
-    //} else {
-
-    //}
-
         float ty,h;
 
         if (min_ytick<=0) {
@@ -198,9 +208,9 @@ void gYAxis::paint(gGraph & w,int left,int top, int width, int height)
         if (min_ytick>=1000000) {
             min_ytick=100;
         }
-    lines=w.backlines();
 
-    GLuint line_color=m_line_color.rgba();
+        //lines=w.backlines();
+
         for (double i=miny; i<=maxy+min_ytick-0.00001; i+=min_ytick) {
             ty=(i - miny) * ymult;
             if (dy<5) {
@@ -209,30 +219,42 @@ void gYAxis::paint(gGraph & w,int left,int top, int width, int height)
                 fd=Format(i*m_yaxis_scale,1);
             }
 
-        GetTextExtent(fd,x,y); // performance bottleneck..
+            GetTextExtent(fd,x,y);
 
             if (x>labelW) labelW=x;
-        h=top+height-ty;
-        if (h<top) continue;
-        w.renderText(fd,left+width-8-x,(h+(y/2.0)),0,m_text_color);
+            h=height-ty;
+            h+=yh;
+            if (h<0)
+                continue;
 
-        lines->add(left+width-4,h,left+width,h,line_color);
+            paint.setBrush(Qt::black);
+            paint.drawText(width-8-x,h+y/2,fd);
+
+            paint.setPen(m_line_color);
+            paint.drawLine(width-4,h,width,h);
 
             double z=(min_ytick/4)*ymult;
             double g=h;
             for (int i=0;i<3;i++) {
                 g+=z;
-            if (g>top+height) break;
-            lines->add(left+width-3,g,left+width,g,line_color);
-            if (lines->full()) {
-                qWarning() << "vertarray bounds exceeded in gYAxis for " << w.title() << "graph" << "MinY =" <<miny << "MaxY =" << maxy << "min_ytick=" <<min_ytick;
-                break;
+                if (g>height+yh) break;
+                paint.drawLine(width-3,g,width,g);
             }
         }
-        if (lines->full()) {
-            qWarning() << "vertarray bounds exceeded in gYAxis for " << w.title() << "graph" << "MinY =" <<miny << "MaxY =" << maxy << "min_ytick=" <<min_ytick;
-            break;
+        paint.end();
+        w.yAxisImage=QGLWidget::convertToGLFormat(pixmap.toImage().mirrored(false,true));
+        w.yAxisImageTex=w.graphView()->bindTexture(w.yAxisImage);
+        w.invalidate_yAxisImage=false;
     }
+
+    if (!w.yAxisImage.isNull()) {
+        glEnable(GL_BLEND);
+        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+        glEnable(GL_TEXTURE_2D);
+        w.graphView()->drawTexture(QPoint(left,(top+height)-w.yAxisImage.height()+3),w.yAxisImageTex);
+        glDisable(GL_TEXTURE_2D);
+        glDisable(GL_BLEND);
+
     }
 }
 const QString gYAxis::Format(EventDataType v, int dp) {