From a26811fc6001ed03e0eb3f671418d1247758aab2 Mon Sep 17 00:00:00 2001
From: Samuel Fadel <samuelfadel@gmail.com>
Date: Thu, 7 Jan 2016 14:55:37 +0100
Subject: Scatterplot: simplified drawing code.

---
 scatterplot.cpp | 44 ++++++++++++++++++++++++--------------------
 1 file changed, 24 insertions(+), 20 deletions(-)

(limited to 'scatterplot.cpp')

diff --git a/scatterplot.cpp b/scatterplot.cpp
index 0812d28..2c9a57a 100644
--- a/scatterplot.cpp
+++ b/scatterplot.cpp
@@ -105,7 +105,7 @@ void Scatterplot::updateMaterials()
     update();
 }
 
-QSGNode *Scatterplot::createSplatNode()
+QSGNode *Scatterplot::newSplatNode()
 {
     if (m_xy.n_rows < 1) {
         return 0;
@@ -129,7 +129,7 @@ QSGNode *Scatterplot::createSplatNode()
     return node;
 }
 
-QSGNode *Scatterplot::createGlyphNodeTree()
+QSGNode *Scatterplot::newGlyphTree()
 {
     // NOTE:
     // The glyph graph is structured as:
@@ -176,30 +176,32 @@ QSGNode *Scatterplot::createGlyphNodeTree()
     return node;
 }
 
-QSGNode *Scatterplot::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *)
+QSGNode *Scatterplot::newSceneGraph()
 {
     // NOTE:
     // The hierarchy in the scene graph is as follows:
     // root [[splatNode] [glyphsRoot [glyph [...]]] [selectionNode]]
-    QSGNode *root = 0;
-    if (!oldNode) {
-        root = new QSGNode;
-        QSGNode *splatNode = createSplatNode();
-        if (splatNode) {
-            root->appendChildNode(splatNode);
-        }
-        QSGNode *glyphTreeRoot = createGlyphNodeTree();
-        if (glyphTreeRoot) {
-            root->appendChildNode(glyphTreeRoot);
-        }
-
-        QSGSimpleRectNode *selectionRectNode = new QSGSimpleRectNode;
-        selectionRectNode->setColor(SELECTION_COLOR);
-        root->appendChildNode(selectionRectNode);
-    } else {
-        root = oldNode;
+    QSGNode *root = new QSGNode;
+    QSGNode *splatNode = newSplatNode();
+    if (splatNode) {
+        root->appendChildNode(splatNode);
+    }
+    QSGNode *glyphTreeRoot = newGlyphTree();
+    if (glyphTreeRoot) {
+        root->appendChildNode(glyphTreeRoot);
     }
 
+    QSGSimpleRectNode *selectionRectNode = new QSGSimpleRectNode;
+    selectionRectNode->setColor(SELECTION_COLOR);
+    root->appendChildNode(selectionRectNode);
+
+    return root;
+}
+
+QSGNode *Scatterplot::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *)
+{
+    QSGNode *root = oldNode ? oldNode : newSceneGraph();
+
     if (m_xy.n_rows < 1) {
         return root;
     }
@@ -210,6 +212,7 @@ QSGNode *Scatterplot::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *)
     QSGNode *glyphsRootNode = root->firstChild()->nextSibling();
     updateGlyphs(glyphsRootNode->firstChild());
 
+    // Change update hints to false; the splat and glyphs were just updated
     if (m_shouldUpdateGeometry) {
         m_shouldUpdateGeometry = false;
     }
@@ -224,6 +227,7 @@ QSGNode *Scatterplot::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *)
         selectionRectNode->setRect(QRectF(m_dragOriginPos, m_dragCurrentPos));
         selectionRectNode->markDirty(QSGNode::DirtyGeometry);
     } else {
+        // Hide selection rect
         selectionRectNode->setRect(QRectF(-1, -1, 0, 0));
     }
 
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