first pass at custom window border

src/ico/ico.c

@@ -0,0 +1,2 @@
+// Copyright (c) 2024 Epic Games Tools
+// Licensed under the MIT license (https://opensource.org/license/mit/)

src/ico/ico.h

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+// Copyright (c) 2024 Epic Games Tools
+// Licensed under the MIT license (https://opensource.org/license/mit/)
+
+#ifndef ICO_H
+#define ICO_H
+
+////////////////////////////////
+//~ rjf: ICO File Format Types
+
+#pragma pack(push, 1)
+
+typedef struct ICO_Header ICO_Header;
+struct ICO_Header
+{
+  U16 reserved_padding; // must be 0
+  U16 image_type; // if 1 -> ICO, if 2 -> CUR
+  U16 num_images;
+};
+
+typedef struct ICO_Entry ICO_Entry;
+struct ICO_Entry
+{
+  U8 image_width_px;
+  U8 image_height_px;
+  U8 num_colors;
+  U8 reserved_padding; // should be 0
+  union
+  {
+    U16 ico_color_planes; // in ICO
+    U16 cur_hotspot_x_px; // in CUR
+  };
+  union
+  {
+    U16 ico_bits_per_pixel; // in ICO
+    U16 cur_hotspot_y_px;   // in CUR
+  };
+  U32 image_data_size;
+  U32 image_data_off;
+};
+
+#pragma pack(pop)
+
+#endif // ICO_H