[tkreuzer] 50112: [VBEMP] Fix rounding error when calculating display size Loosely based on patch by neoman. Fixes gdi32_winetest:mapping See issue #5790 for more details.

Author: tkreuzer
Date: Thu Dec 23 12:11:19 2010
New Revision: 50112

URL: http://svn.reactos.org/svn/reactos?rev=50112&view=rev
Log:
[VBEMP]
Fix rounding error when calculating display size
Loosely based on patch by neoman.
Fixes gdi32_winetest:mapping

See issue #5790 for more details.

Modified:
    trunk/reactos/drivers/video/miniport/vbe/vbemp.c

Modified: trunk/reactos/drivers/video/miniport/vbe/vbemp.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/drivers/video/miniport/vbe/...
==============================================================================
--- trunk/reactos/drivers/video/miniport/vbe/vbemp.c [iso-8859-1] (original)
+++ trunk/reactos/drivers/video/miniport/vbe/vbemp.c [iso-8859-1] Thu Dec 23 12:11:19 2010
@@ -847,6 +847,7 @@
    ULONG VideoModeId)
 {
    PVBE_MODEINFO VBEMode = &DeviceExtension->ModeInfo[VideoModeId];
+   ULONG dpi;

VideoMode->Length = sizeof(VIDEO_MODE_INFORMATION);
    VideoMode->ModeIndex = VideoModeId;
@@ -860,9 +861,10 @@
    VideoMode->BitsPerPlane = VBEMode->BitsPerPixel / VBEMode->NumberOfPlanes;
    VideoMode->Frequency = 1;

-   /* Assume 96DPI and 25.4 millimeters per inch */
-   VideoMode->XMillimeter = VBEMode->XResolution * 254 / 960;
-   VideoMode->YMillimeter = VBEMode->YResolution * 254 / 960;
+   /* Assume 96DPI and 25.4 millimeters per inch, round to nearest */
+   dpi = 96;
+   VideoMode->XMillimeter = ((ULONGLONG)VBEMode->XResolution * 254 + (dpi * 5)) / (dpi * 10);
+   VideoMode->YMillimeter = ((ULONGLONG)VBEMode->YResolution * 254 + (dpi * 5)) / (dpi * 10);

if (VBEMode->BitsPerPixel > 8)
    {