gdiplus: Improve GdipFillRectangles parameter validation.

dlls/gdiplus/graphics.c

@@ -3747,7 +3747,7 @@ GpStatus WINGDIPAPI GdipFillRectangles(GpGraphics *graphics, GpBrush *brush, GDI
 
     TRACE("(%p, %p, %p, %d)\n", graphics, brush, rects, count);
 
-    if(!rects)
+    if(!graphics || !brush || !rects || count <= 0)
         return InvalidParameter;
 
     if (graphics->image && graphics->image->type == ImageTypeMetafile)

dlls/gdiplus/tests/graphics.c

@@ -5493,6 +5493,52 @@ static void test_clipping_2(void)
     DeleteDC(hdc);
 }
 
+
+static void test_GdipFillRectangles(void)
+{
+    GpStatus status;
+    GpGraphics *graphics = NULL;
+    GpBrush *brush = NULL;
+    HDC hdc = GetDC( hwnd );
+    GpRectF rects[2] = {{0,0,10,10}, {10,10,10,10}};
+
+    ok(hdc != NULL, "Expected HDC to be initialized\n");
+
+    status = GdipCreateFromHDC(hdc, &graphics);
+    expect(Ok, status);
+    ok(graphics != NULL, "Expected graphics to be initialized\n");
+
+    status = GdipCreateSolidFill((ARGB)0xffff00ff, (GpSolidFill**)&brush);
+    expect(Ok, status);
+    ok(brush != NULL, "Expected brush to be initialized\n");
+
+    status = GdipFillRectangles(NULL, brush, rects, 2);
+    expect(InvalidParameter, status);
+
+    status = GdipFillRectangles(graphics, NULL, rects, 2);
+    expect(InvalidParameter, status);
+
+    status = GdipFillRectangles(graphics, brush, NULL, 2);
+    expect(InvalidParameter, status);
+
+    status = GdipFillRectangles(graphics, brush, rects, 0);
+    expect(InvalidParameter, status);
+
+    status = GdipFillRectangles(graphics, brush, rects, -1);
+    expect(InvalidParameter, status);
+
+    status = GdipFillRectangles(graphics, brush, rects, 1);
+    expect(Ok, status);
+
+    status = GdipFillRectangles(graphics, brush, rects, 2);
+    expect(Ok, status);
+
+    GdipDeleteBrush(brush);
+    GdipDeleteGraphics(graphics);
+
+    ReleaseDC(hwnd, hdc);
+}
+
 START_TEST(graphics)
 {
     struct GdiplusStartupInput gdiplusStartupInput;
@@ -5563,6 +5609,7 @@ START_TEST(graphics)
     test_getdc_scaled();
     test_alpha_hdc();
     test_bitmapfromgraphics();
+    test_GdipFillRectangles();
 
     GdiplusShutdown(gdiplusToken);
     DestroyWindow( hwnd );