Этап 7

Minint.Core/Services/Impl/DrawingService.cs

@@ -0,0 +1,43 @@
+using Minint.Core.Models;
+
+namespace Minint.Core.Services.Impl;
+
+public sealed class DrawingService : IDrawingService
+{
+    public void ApplyBrush(MinintLayer layer, int cx, int cy, int radius, int colorIndex, int width, int height)
+    {
+        foreach (var (x, y) in GetBrushMask(cx, cy, radius, width, height))
+            layer.Pixels[y * width + x] = colorIndex;
+    }
+
+    public void ApplyEraser(MinintLayer layer, int cx, int cy, int radius, int width, int height)
+    {
+        foreach (var (x, y) in GetBrushMask(cx, cy, radius, width, height))
+            layer.Pixels[y * width + x] = 0;
+    }
+
+    public List<(int X, int Y)> GetBrushMask(int cx, int cy, int radius, int width, int height)
+    {
+        var mask = new List<(int, int)>();
+        int r = Math.Max(radius, 0);
+        int r2 = r * r;
+
+        int xMin = Math.Max(0, cx - r);
+        int xMax = Math.Min(width - 1, cx + r);
+        int yMin = Math.Max(0, cy - r);
+        int yMax = Math.Min(height - 1, cy + r);
+
+        for (int py = yMin; py <= yMax; py++)
+        {
+            int dy = py - cy;
+            for (int px = xMin; px <= xMax; px++)
+            {
+                int dx = px - cx;
+                if (dx * dx + dy * dy <= r2)
+                    mask.Add((px, py));
+            }
+        }
+
+        return mask;
+    }
+}