[f-spot/icon-view-cleanup: 22/24] Clean up drawing code in CellGridView

[Mike Gemünde <mgemuende src gnome org>]

commit cda297b2ea9c71c1831e0aafbb9e62d4179a9717
Author: Mike Gemünde <mike gemuende de>
Date:   Mon Aug 16 19:32:55 2010 +0200

    Clean up drawing code in CellGridView
    
    I love this kind of removing code...

 src/Clients/MainApp/FSpot.Widgets/CellGridView.cs |   58 ++++++++++-----------
 1 files changed, 28 insertions(+), 30 deletions(-)
---
diff --git a/src/Clients/MainApp/FSpot.Widgets/CellGridView.cs b/src/Clients/MainApp/FSpot.Widgets/CellGridView.cs
index 5e327f0..8ed2cd8 100644
--- a/src/Clients/MainApp/FSpot.Widgets/CellGridView.cs
+++ b/src/Clients/MainApp/FSpot.Widgets/CellGridView.cs
@@ -11,6 +11,7 @@
  */
 
 using System;
+using System.Collections.Generic;
 
 using Gtk;
 using Gdk;
@@ -255,6 +256,31 @@ namespace FSpot.Widgets
             return bounds;
         }
 
+        // TODO: move to utility class
+        protected int Limit (int lower_bound, int value, int upper_bound)
+        {
+            return Math.Max (lower_bound, Math.Min (value, upper_bound));
+        }
+
+        public IEnumerable<int> CellsInRect (Rectangle area)
+        {
+            int start_cell_column = Limit (0, (area.X - border_size) / cell_width, Allocation.Width);
+            int start_cell_row = Limit (0, (area.Y - border_size) / cell_height, Allocation.Height);
+
+            int end_cell_column = Limit (0, (area.X + area.Width - border_size) / cell_width, Allocation.Width);
+            int end_cell_row = Limit (0, (area.Y + area.Height - border_size) / cell_height, Allocation.Height);
+
+
+            for (int cell_row = start_cell_row; cell_row <= end_cell_row; cell_row ++) {
+
+                for (int cell_column = start_cell_column; cell_column <= end_cell_column; cell_column ++) {
+
+                    yield return cell_column + cell_row * cells_per_row;
+
+                }
+            }
+        }
+
         public void ScrollTo (int cell_num)
         {
             ScrollTo (cell_num, true);
@@ -421,36 +447,8 @@ namespace FSpot.Widgets
 
         private void DrawAllCells (Gdk.Rectangle area)
         {
-            if (cell_width == 0 || cell_height == 0)
-                return;
-
-            int start_cell_column = Math.Max ((area.X - border_size) / cell_width, 0);
-            int start_cell_row = Math.Max ((area.Y - border_size) / cell_height, 0);
-            int start_cell_num = start_cell_column + start_cell_row * cells_per_row;
-
-            int start_cell_x, cell_y;
-            CellPosition (start_cell_num, out start_cell_x, out cell_y);
-
-            int end_cell_column = Math.Max ((area.X + area.Width - border_size) / cell_width, 0);
-            int end_cell_row = Math.Max ((area.Y + area.Height - border_size) / cell_height, 0);
-
-            int num_rows = end_cell_row - start_cell_row + 1;
-            int num_cols = Math.Min (end_cell_column - start_cell_column + 1, cells_per_row - start_cell_column);
-
-            int i, cell_num;
-
-            for (i = 0, cell_num = start_cell_num; i < num_rows && cell_num < cell_count; i ++) {
-
-                int cell_x = start_cell_x;
-
-                //Log.DebugFormat ("Drawing row {0}", start_cell_row + i);
-                for (int j = 0; j < num_cols && cell_num + j < cell_count; j ++) {
-                    DrawCell (cell_num + j, area);
-                    cell_x += cell_width;
-                }
-
-                cell_y += cell_height;
-                cell_num += cells_per_row;
+            foreach (var cell_num in CellsInRect (area)) {
+                DrawCell (cell_num, area);
             }
         }