Smooth lines

Assets/Drawing/Drawable Frame/DrawableFrame.cs.meta

@@ -4,7 +4,7 @@ MonoImporter:
   externalObjects: {}
   serializedVersion: 2
   defaultReferences: []
-  executionOrder: 100
+  executionOrder: -50
   icon: {instanceID: 0}
   userData: 
   assetBundleName: 

Assets/Drawing/Drawable Frame/PencilTool.cs

@@ -4,9 +4,14 @@ using UnityEngine;
 
 public class PencilTool : DrawTool
 {
-    public Color color = Color.black;
+    public Color selectedColor = Color.black;
     public float size = 1f;
     
+    protected Color[] colors;
+    
+    private Vector2Int? previousPixel;
+    private Vector2Int? pixel;
+
     protected Vector2Int? HoveredPixel() {
         Vector2 worldPoint = Camera.main.ScreenToWorldPoint(Input.mousePosition);
         if(frame.Bounds.Contains(worldPoint)) {
@@ -19,31 +24,107 @@ public class PencilTool : DrawTool
 
     protected override void Start() {
         base.Start();
-        InvokeRepeating("Apply", 0.05f, 0.05f);
+        colors = frame.texture.GetPixels();
     }
 
     protected void Update() {
-        Color[] colors = frame.texture.GetPixels();
+        previousPixel = pixel;
         if(Input.GetMouseButton(0)) {
-            Vector2Int? pixel = HoveredPixel();
+            pixel = HoveredPixel();
             if(pixel.HasValue) {
-                int x_start = Mathf.Clamp(Mathf.CeilToInt((float)pixel.Value.x - size), 0, frame.resolution.x);
+                if(previousPixel.HasValue) {
-                int x_end = Mathf.Clamp(Mathf.CeilToInt((float)pixel.Value.x + size), 0, frame.resolution.x);
+                    DrawBresenhamsThickLine(previousPixel.Value, pixel.Value, size, selectedColor);
-                int y_start = Mathf.Clamp(Mathf.CeilToInt((float)pixel.Value.y - size), 0, frame.resolution.y);
+                }
-                int y_end = Mathf.Clamp(Mathf.CeilToInt((float)pixel.Value.y + size), 0, frame.resolution.y);
+                else {
-                for(int x = x_start; x < x_end; x++) {
+                    DrawFilledCircle(pixel.Value, size, selectedColor);
-                    for(int y = y_start; y < y_end; y++) {
+                }
-                        if(Vector2Int.Distance(new Vector2Int(x, y), pixel.Value) < size) {
+            }
+            Apply();
+        }
+        else {
+            pixel = null;
+        }
+    }
+
+    protected void DrawPixel(int x, int y, Color color) {
+        if(x < 0 || x >= frame.resolution.x || y < 0 || y >= frame.resolution.y) return;
         colors[x + y*frame.resolution.x] = color;
     }
+
+    protected void DrawCircleEightPoints(Vector2Int center, int x_radius, int y_radius, Color color) {
+        DrawPixel(center.x+x_radius, center.y+y_radius, color); 
+        DrawPixel(center.x-x_radius, center.y+y_radius, color); 
+        DrawPixel(center.x+x_radius, center.y-y_radius, color); 
+        DrawPixel(center.x-x_radius, center.y-y_radius, color); 
+        DrawPixel(center.x+y_radius, center.y+x_radius, color); 
+        DrawPixel(center.x-y_radius, center.y+x_radius, color); 
+        DrawPixel(center.x+y_radius, center.y-x_radius, color); 
+        DrawPixel(center.x-y_radius, center.y-x_radius, color); 
+    }
+
+    // No idea on how does it work
+    // https://www.geeksforgeeks.org/bresenhams-circle-drawing-algorithm/
+    protected void DrawBresenhamEmptyCircle(Vector2Int center, int radius, Color color) {
+        int x = 0;
+        int y = radius;
+        int d = 3 - 2 * radius;
+        DrawCircleEightPoints(center, x, y, color);
+        while(y >= x) {
+            x++;
+            if(d > 0) {
+                y--;
+                d = d + 4 * (x - y) + 10;
+            }
+            else {
+                d = d + 4 * x + 6;
+            }
+            DrawCircleEightPoints(center, x, y, color);
+        }
+    }
+
+    protected void DrawFilledCircle(Vector2Int center, float radius, Color color) {
+        int x_start = Mathf.CeilToInt((float)center.x - radius);
+        int x_end = Mathf.CeilToInt((float)center.x + radius);
+        int y_start = Mathf.CeilToInt((float)center.y - radius);
+        int y_end = Mathf.CeilToInt((float)center.y + radius);
+        for(int x = x_start; x < x_end; x++) {
+            for(int y = y_start; y < y_end; y++) {
+                if(Vector2Int.Distance(new Vector2Int(x, y), center) < radius) {
+                    DrawPixel(x, y, color);
                 }
             }
         }
     }
-        frame.texture.SetPixels(colors);
+
+    // http://www.roguebasin.com/index.php?title=Bresenham%27s_Line_Algorithm
+    protected void DrawBresenhamsThickLine(Vector2Int start, Vector2Int end, float radius, Color color) {
+        int start_x = start.x, start_y = start.y, end_x = end.x, end_y = end.y;
+        bool steep = Mathf.Abs(end_y - start_y) > Mathf.Abs(end_x - start_x);
+        if (steep) {
+            Utils.Swap<int>(ref start_x, ref start_y);
+            Utils.Swap<int>(ref end_x, ref end_y); 
+        }
+        if (start_x > end_x) {
+            Utils.Swap<int>(ref start_x, ref end_x);
+            Utils.Swap<int>(ref start_y, ref end_y); 
+        }
+        int dX = (end_x - start_x), dY = Mathf.Abs(end_y - start_y), err = (dX / 2), ystep = (start_y < end_y ? 1 : -1), y = start_y;
+
+        for (int x = start_x; x <= end_x; ++x)
+        {
+            if(steep) {
+                DrawFilledCircle(new Vector2Int(y, x), radius, color);
+            }
+            else {
+                DrawFilledCircle(new Vector2Int(x, y), radius, color);
+            }
+            err = err - dY;
+            if (err < 0) { y += ystep;  err += dX; }
+        }
     }
 
     protected void Apply() {
+        frame.texture.SetPixels(colors);
         frame.texture.Apply();
     }
 }

Assets/Drawing/Drawable Frame/SetSpriteFromDrawableFrame.cs.meta

@@ -4,7 +4,7 @@ MonoImporter:
   externalObjects: {}
   serializedVersion: 2
   defaultReferences: []
-  executionOrder: 200
+  executionOrder: 0
   icon: {instanceID: 0}
   userData: 
   assetBundleName: 

Assets/Drawing/PencilColorFromButtonColor.cs

@@ -16,6 +16,6 @@ public class PencilColorFromButtonColor : MonoBehaviour
 
     public void OnClick()
     {
-        pencil.color = image.color;
+        pencil.selectedColor = image.color;
     }
 }

Assets/Swap.cs

@@ -0,0 +1,6 @@
+
+public class Utils {
+    public static void Swap<T>(ref T lhs, ref T rhs) {
+        T temp; temp = lhs; lhs = rhs; rhs = temp; 
+    }
+}

Assets/Swap.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 12f494a09d5848e4c8843d84f864396e
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: