Base/Forms/GraphForm.Designer.cs

@@ -41,6 +41,7 @@
             MenuEquationsIntegral = new ToolStripMenuItem();
             MenuMisc = new ToolStripMenuItem();
             MenuMiscCaches = new ToolStripMenuItem();
+            MiscMenuPreload = new ToolStripMenuItem();
             GraphMenu.SuspendLayout();
             SuspendLayout();
             // 
@@ -129,7 +130,7 @@
             // 
             // MenuMisc
             // 
-            MenuMisc.DropDownItems.AddRange(new ToolStripItem[] { MenuMiscCaches });
+            MenuMisc.DropDownItems.AddRange(new ToolStripItem[] { MenuMiscCaches, MiscMenuPreload });
             MenuMisc.Name = "MenuMisc";
             MenuMisc.Size = new Size(83, 38);
             MenuMisc.Text = "Misc";
@@ -141,6 +142,13 @@
             MenuMiscCaches.Text = "View Caches";
             MenuMiscCaches.Click += MenuMiscCaches_Click;
             // 
+            // MiscMenuPreload
+            // 
+            MiscMenuPreload.Name = "MiscMenuPreload";
+            MiscMenuPreload.Size = new Size(359, 44);
+            MiscMenuPreload.Text = "Preload Cache";
+            MiscMenuPreload.Click += MiscMenuPreload_Click;
+            // 
             // GraphForm
             // 
             AutoScaleDimensions = new SizeF(13F, 32F);
@@ -172,5 +180,6 @@
         private ToolStripMenuItem MenuEquationsIntegral;
         private ToolStripMenuItem MenuMisc;
         private ToolStripMenuItem MenuMiscCaches;
+        private ToolStripMenuItem MiscMenuPreload;
     }
 }

Base/Forms/GraphForm.cs

@@ -1,4 +1,5 @@
 using Graphing.Graphables;
+using Graphing.Parts;
 using System.Drawing.Drawing2D;
 
 namespace Graphing.Forms;
@@ -200,6 +201,10 @@ public partial class GraphForm : Form
         PaintGrid(g);
         PaintUnits(g);
 
+        Point clientMousePos = PointToClient(Cursor.Position);
+        Float2 graphMousePos = ScreenSpaceToGraphSpace(new(clientMousePos.X,
+                                                           clientMousePos.Y));
+
         // Draw the actual graphs.
         for (int i = 0; i < ables.Count; i++)
         {
@@ -207,6 +212,18 @@ public partial class GraphForm : Form
             Brush graphBrush = new SolidBrush(ables[i].Color);
             Pen graphPen = new(graphBrush, DpiFloat * 3 / 192);
             foreach (IGraphPart gp in lines) gp.Render(this, g, graphPen);
+
+            // Equation selection detection.
+            // This system lets you select multiple graphs, and that's cool by me.
+            if (ableDrag)
+            {
+                if (ables[i].ShouldSelectGraphable(this, graphMousePos, 2.5))
+                {
+                    Float2 selectedPoint = ables[i].GetSelectedPoint(this, graphMousePos);
+                    GraphUiCircle select = new(selectedPoint, 8);
+                    select.Render(this, g, graphPen);
+                }
+            }
         }
 
         base.OnPaint(e);
@@ -227,12 +244,29 @@ public partial class GraphForm : Form
     private bool mouseDrag = false;
     private Int2 initialMouseLocation;
     private Float2 initialScreenCenter;
+
+    private bool ableDrag = false;
     protected override void OnMouseDown(MouseEventArgs e)
+    {
+        if (!mouseDrag)
+        {
+            Point clientMousePos = PointToClient(Cursor.Position);
+            Float2 graphMousePos = ScreenSpaceToGraphSpace(new(clientMousePos.X,
+                                                               clientMousePos.Y));
+            foreach (Graphable able in Graphables)
+            {
+                if (able.ShouldSelectGraphable(this, graphMousePos, 1)) ableDrag = true;
+            }
+            if (ableDrag) Invalidate(false);
+        }
+
+        if (!ableDrag)
         {
             mouseDrag = true;
             initialMouseLocation = new Int2(Cursor.Position.X, Cursor.Position.Y);
             initialScreenCenter = ScreenCenter;
         }
+    }
     protected override void OnMouseUp(MouseEventArgs e)
     {
         if (mouseDrag)
@@ -242,9 +276,10 @@ public partial class GraphForm : Form
             Float2 graphDiff = new(pixelDiff.x * ZoomLevel / Dpi.x, pixelDiff.y * ZoomLevel / Dpi.y);
             ScreenCenter = new(initialScreenCenter.x + graphDiff.x,
                                initialScreenCenter.y + graphDiff.y);
-            Invalidate(false);
         }
         mouseDrag = false;
+        ableDrag = false;
+        Invalidate(false);
     }
     protected override void OnMouseMove(MouseEventArgs e)
     {
@@ -257,6 +292,7 @@ public partial class GraphForm : Form
                                initialScreenCenter.y + graphDiff.y);
             Invalidate(false);
         }
+        else if (ableDrag) Invalidate(false);
     }
     protected override void OnMouseWheel(MouseEventArgs e)
     {
@@ -425,4 +461,17 @@ public partial class GraphForm : Form
         cacheForm.TopMost = true;
         cacheForm.Show();
     }
+    private void MiscMenuPreload_Click(object sender, EventArgs e)
+    {
+        Float2 min = MinVisibleGraph, max = MaxVisibleGraph;
+        Float2 add = new(max.x - min.x, max.y - min.y);
+        add.x *= 0.75; // Expansion
+        add.y *= 0.75; //
+
+        Float2 xRange = new(min.x - add.x, max.x + add.x),
+               yRange = new(min.y - add.y, max.y + add.y);
+
+        foreach (Graphable able in Graphables) able.Preload(xRange, yRange);
+        Invalidate(false);
+    }
 }

Base/Graphable.cs

@@ -1,5 +1,4 @@
 using Graphing.Forms;
-using Graphing.Parts;
 
 namespace Graphing;
 
@@ -33,4 +32,8 @@ public abstract class Graphable
 
     public abstract void EraseCache();
     public abstract long GetCacheBytes();
+    public abstract void Preload(Float2 xRange, Float2 yRange);
+
+    public abstract bool ShouldSelectGraphable(in GraphForm graph, Float2 graphMousePos, double factor);
+    public abstract Float2 GetSelectedPoint(in GraphForm graph, Float2 graphMousePos);
 }

Base/Graphables/ColumnTable.cs

@@ -48,4 +48,9 @@ public class ColumnTable : Graphable
 
         return items;
     }
+
+    public override bool ShouldSelectGraphable(in GraphForm graph, Float2 graphMousePos, double factor) => false;
+    public override Float2 GetSelectedPoint(in GraphForm graph, Float2 graphMousePos) => default;
+
+    public override void Preload(Float2 xRange, Float2 yRange) { }
 }

Base/Graphables/Equation.cs

@@ -96,6 +96,30 @@ public class Equation : Graphable
     public override Graphable DeepCopy() => new Equation(equ);
 
     public override long GetCacheBytes() => cache.Count * 16;
+
+    public override bool ShouldSelectGraphable(in GraphForm graph, Float2 graphMousePos, double factor)
+    {
+        Int2 screenMousePos = graph.GraphSpaceToScreenSpace(graphMousePos);
+
+        (_, _, int index) = NearestCachedPoint(graphMousePos.x);
+        Int2 screenCachePos = graph.GraphSpaceToScreenSpace(cache[index]);
+
+        double allowedDist = factor * graph.DpiFloat * 80 / 192;
+
+        Int2 dist = new(screenCachePos.x - screenMousePos.x,
+                        screenCachePos.y - screenMousePos.y);
+        double totalDist = Math.Sqrt(dist.x * dist.x + dist.y * dist.y);
+        return totalDist <= allowedDist;
+    }
+    public override Float2 GetSelectedPoint(in GraphForm graph, Float2 graphMousePos)
+    {
+        return new(graphMousePos.x, GetFromCache(graphMousePos.x, 0.001));
+    }
+
+    public override void Preload(Float2 xRange, Float2 yRange)
+    {
+        for (double x = xRange.x; x <= xRange.y; x += 1e-3) GetFromCache(x, 1e-4);
+    }
 }
 
 public delegate double EquationDelegate(double x);

Base/Graphables/SlopeField.cs

@@ -74,6 +74,11 @@ public class SlopeField : Graphable
 
     public override void EraseCache() => cache.Clear();
     public override long GetCacheBytes() => cache.Count * 48;
+
+    public override bool ShouldSelectGraphable(in GraphForm graph, Float2 graphMousePos, double factor) => false;
+    public override Float2 GetSelectedPoint(in GraphForm graph, Float2 graphMousePos) => default;
+
+    public override void Preload(Float2 xRange, Float2 yRange) { }
 }
 
 public delegate double SlopeFieldsDelegate(double x, double y);

Base/Graphables/TangentLine.cs

@@ -48,4 +48,9 @@ public class TangentLine : Graphable
 
     public override void EraseCache() { }
     public override long GetCacheBytes() => 0;
+
+    public override bool ShouldSelectGraphable(in GraphForm graph, Float2 graphMousePos, double factor) => false;
+    public override Float2 GetSelectedPoint(in GraphForm graph, Float2 graphMousePos) => default;
+
+    public override void Preload(Float2 xRange, Float2 yRange) { }
 }