Function DrawCursor

Source/engine/render/scrollrt.cpp:263–314

* @brief Save the content behind the cursor to a temporary buffer, then draw the cursor. */

 * @brief Save the content behind the cursor to a temporary buffer, then draw the cursor.
 */
void DrawCursor(const Surface &out)
{
	DrawnCursor &cursor = GetDrawnCursor();
	if (IsHardwareCursor()) {
		SetHardwareCursorVisible(ShouldShowCursor());
		cursor.rect.size = { 0, 0 };
		return;
	}

	if (pcurs <= CURSOR_NONE || !ShouldShowCursor()) {
		cursor.rect.size = { 0, 0 };
		return;
	}

	Size cursSize = GetInvItemSize(pcurs);
	if (cursSize.width == 0 || cursSize.height == 0) {
		cursor.rect.size = { 0, 0 };
		return;
	}

	constexpr auto Clip = [](int &pos, int &length, int posEnd) {
		if (pos + length <= 0 || pos >= posEnd) {
			pos = 0;
			length = 0;
		} else if (pos < 0) {
			length += pos;
			pos = 0;
		} else if (pos + length > posEnd) {
			length = posEnd - pos;
		}
	};

	// Copy the buffer before the item cursor and its 1px outline are drawn to a temporary buffer.
	const int outlineWidth = !MyPlayer->HoldItem.isEmpty() ? 1 : 0;
	Displacement offset = !MyPlayer->HoldItem.isEmpty() ? Displacement { cursSize / 2 } : Displacement { 0 };
	Point cursPosition = MousePosition - offset;

	Rectangle &rect = cursor.rect;
	rect.position.x = cursPosition.x - outlineWidth;
	rect.size.width = cursSize.width + 2 * outlineWidth;
	Clip(rect.position.x, rect.size.width, out.w());

	rect.position.y = cursPosition.y - outlineWidth;
	rect.size.height = cursSize.height + 2 * outlineWidth;
	Clip(rect.position.y, rect.size.height, out.h());

	if (rect.size.width == 0 || rect.size.height == 0)
		return;

	BlitCursor(cursor.behindBuffer, rect.size.width, &out[rect.position], out.pitch(), rect.size.width, rect.size.height);
	DrawSoftwareCursor(out, cursPosition + Displacement { 0, cursSize.height - 1 }, pcurs);
}

/**
 * @brief Render a missile sprite