(svn r6184) Remove the unused (because it was NULL in all callers) second parameter of FillDrawPixelInfo() and simplify some expressions

gfx.c

@@ -1880,43 +1880,43 @@ void MarkWholeScreenDirty(void)
 	SetDirtyBlocks(0, 0, _screen.width, _screen.height);
 }
 
-bool FillDrawPixelInfo(DrawPixelInfo *n, const DrawPixelInfo *o, int left, int top, int width, int height)
+bool FillDrawPixelInfo(DrawPixelInfo *n, int left, int top, int width, int height)
 {
-	int t;
-
-	if (o == NULL) o = _cur_dpi;
+	const DrawPixelInfo *o = _cur_dpi;
 
 	n->zoom = 0;
 
 	assert(width > 0);
 	assert(height > 0);
 
-	n->left = 0;
 	if ((left -= o->left) < 0) {
 		width += left;
 		if (width < 0) return false;
 		n->left = -left;
 		left = 0;
+	} else {
+		n->left = 0;
 	}
 
-	if ((t=width + left - o->width) > 0) {
-		width -= t;
+	if (width > o->width - left) {
+		width = o->width - left;
 		if (width < 0) return false;
 	}
 	n->width = width;
 
-	n->top = 0;
 	if ((top -= o->top) < 0) {
 		height += top;
 		if (height < 0) return false;
 		n->top = -top;
 		top = 0;
+	} else {
+		n->top = 0;
 	}
 
 	n->dst_ptr = o->dst_ptr + left + top * (n->pitch = o->pitch);
 
-	if ((t=height + top - o->height) > 0) {
-		height -= t;
+	if (height > o->height - top) {
+		height = o->height - top;
 		if (height < 0) return false;
 	}
 	n->height = height;

gfx.h

@@ -85,7 +85,7 @@ void MarkWholeScreenDirty(void);
 
 void GfxInitPalettes(void);
 
-bool FillDrawPixelInfo(DrawPixelInfo* n, const DrawPixelInfo* o, int left, int top, int width, int height);
+bool FillDrawPixelInfo(DrawPixelInfo* n, int left, int top, int width, int height);
 
 /* window.c */
 void DrawOverlappedWindowForAll(int left, int top, int right, int bottom);

main_gui.c

@@ -2110,7 +2110,7 @@ static bool DrawScrollingStatusText(const NewsItem *ni, int pos)
 		}
 	}
 
-	if (!FillDrawPixelInfo(&tmp_dpi, NULL, 141, 1, 358, 11)) return true;
+	if (!FillDrawPixelInfo(&tmp_dpi, 141, 1, 358, 11)) return true;
 
 	old_dpi = _cur_dpi;
 	_cur_dpi = &tmp_dpi;

rail_gui.c

@@ -674,7 +674,7 @@ static void StationBuildWndProc(Window *w, WindowEvent *e)
 		y_offset = newstations ? 90 : 0;
 
 		/* Set up a clipping area for the '/' station preview */
-		if (FillDrawPixelInfo(&tmp_dpi, NULL, 7, 26 + y_offset, 66, 48)) {
+		if (FillDrawPixelInfo(&tmp_dpi, 7, 26 + y_offset, 66, 48)) {
 			old_dpi = _cur_dpi;
 			_cur_dpi = &tmp_dpi;
 			if (!DrawStationTile(32, 16, _cur_railtype, AXIS_X, _railstation.station_class, _railstation.station_type)) {
@@ -684,7 +684,7 @@ static void StationBuildWndProc(Window *w, WindowEvent *e)
 		}
 
 		/* Set up a clipping area for the '\' station preview */
-		if (FillDrawPixelInfo(&tmp_dpi, NULL, 75, 26 + y_offset, 66, 48)) {
+		if (FillDrawPixelInfo(&tmp_dpi, 75, 26 + y_offset, 66, 48)) {
 			old_dpi = _cur_dpi;
 			_cur_dpi = &tmp_dpi;
 			if (!DrawStationTile(32, 16, _cur_railtype, AXIS_Y, _railstation.station_class, _railstation.station_type)) {

smallmap_gui.c

@@ -836,7 +836,7 @@ static void SmallMapWindowProc(Window *w, WindowEvent *e)
 			}
 		}
 
-		if (!FillDrawPixelInfo(&new_dpi, NULL, 3, 17, w->width - 28 + 22, w->height - 64 - 11))
+		if (!FillDrawPixelInfo(&new_dpi, 3, 17, w->width - 28 + 22, w->height - 64 - 11))
 			return;
 
 		DrawSmallMap(&new_dpi, w, _smallmap_type, _smallmap_show_towns);

train_gui.c

@@ -361,7 +361,7 @@ static void DrawTrainImage(const Vehicle *v, int x, int y, int count, int skip,
 	int highlight_l = 0;
 	int highlight_r = 0;
 
-	if (!FillDrawPixelInfo(&tmp_dpi, NULL, x - 2, y - 1, count + 1, 14)) return;
+	if (!FillDrawPixelInfo(&tmp_dpi, x - 2, y - 1, count + 1, 14)) return;
 
 	count = (count * 8) / _traininfo_vehicle_width;