[Bug 60057] New: gdiplus: GdipCloneBitmapArea drops trailing pixels for 1bpp/4bpp bitmaps with non-byte-aligned width

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=60057

            Bug ID: 60057
           Summary: gdiplus: GdipCloneBitmapArea drops trailing pixels for
                    1bpp/4bpp bitmaps with non-byte-aligned width
           Product: Wine
           Version: 11.13
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: gdiplus
          Assignee: [e-mail]
          Reporter: [e-mail]
  Target Milestone: ---
      Distribution: ---

When cloning a bitmap whose pixel format is less than 8 bits per pixel and
whose width is not a whole number of bytes, the rightmost pixels of every row
are not copied. They retain the destination bitmap's initial zero value, which
typically renders as black.

This issue affects PixelFormat1bppIndexed (loses width%8 columns) &
PixelFormat4bppIndexed (loses 1 column if width is odd).

How to reproduce:
1.Create a PixelFormat1bppIndexed bitmap of width 10, any height, with all
pixels set to a non-zero palette index;
2. Clone it using GdipCloneBitmapArea();
3. Read back the pixels of the clone.
The resulting bitmap will have lost data in the last two columns of the image.

This is caused by image.c convert_pixels() same-format path algorithm rounding
down when calculating byte width of a row:
UINT widthbytes = PIXELFORMATBPP(src_format) * width / 8;
which should be easily fixable with:
UINT widthbytes = (PIXELFORMATBPP(src_format) * width + 7) / 8;

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