ImageMagick 7.0.8-34 has a "use of uninitialized value" vulnerability in the ReadPANGOImage function in coders/pango.c.
### Prerequisites

- [ Y ] I have written a descriptive issue title
- [ Y ] I have verified that I am using the latest version of ImageMagick
- [ Y ] I have searched [open](https://github.com/ImageMagick/ImageMagick/issues) and [closed](https://github.com/ImageMagick/ImageMagick/issues?q=is%3Aissue+is%3Aclosed) issues to ensure it has not already been reported

### Description
<!-- A description of the bug or feature -->
There a use-of-uninitialized-value vulnerability in function ReadPANGOImage in coders/pango.c.

```
  assert(image_info != (const ImageInfo *) NULL);
  assert(image_info->signature == MagickCoreSignature);
  if (image_info->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",
      image_info->filename);
  assert(exception != (ExceptionInfo *) NULL);
  assert(exception->signature == MagickCoreSignature);
  image=AcquireImage(image_info,exception);
  (void) ResetImagePage(image,"0x0+0+0");
```
https://github.com/ImageMagick/ImageMagick/blob/master/coders/pango.c#L179

We should call `SetImageBackgroundColor` when condition `image->columns !=0 && image->rows !=0` satisfies. Otherwise, there will be a use-of-unintialized-value vulnerablity.

See https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=11930, https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=6616, https://github.com/ImageMagick/ImageMagick/commit/18df5773b5efbd2c9dc54c9caa021febf486bd22 and https://github.com/ImageMagick/ImageMagick/commit/f1fb7816a60c7c68d7ac037975c5aa95b6dcf8dd for more details.
Use-of-uninitialized-value in function ReadPANGOImage
This is a GitHub Issue
repo:ImageMagick
owner:ImageMagick
Title : Use-of-uninitialized-value in function ReadPANGOImage
Issue date:

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### Prerequisites

- [ Y ] I have written a descriptive issue title
- [ Y ] I have verified that I am using the latest version of ImageMagick
- [ Y ] I have searched [open](https://github.com/ImageMagick/ImageMagick/issues) and [closed](https://github.com/ImageMagick/ImageMagick/issues?q=is%3Aissue+is%3Aclosed) issues to ensure it has not already been reported

### Description
<!-- A description of the bug or feature -->
There a use-of-uninitialized-value vulnerability in function ReadPANGOImage in coders/pango.c.

```
  assert(image_info != (const ImageInfo *) NULL);
  assert(image_info->signature == MagickCoreSignature);
  if (image_info->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",
      image_info->filename);
  assert(exception != (ExceptionInfo *) NULL);
  assert(exception->signature == MagickCoreSignature);
  image=AcquireImage(image_info,exception);
  (void) ResetImagePage(image,"0x0+0+0");
```
https://github.com/ImageMagick/ImageMagick/blob/master/coders/pango.c#L179

We should call `SetImageBackgroundColor` when condition `image->columns !=0 && image->rows !=0` satisfies. Otherwise, there will be a use-of-unintialized-value vulnerablity.

See https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=11930, https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=6616, https://github.com/ImageMagick/ImageMagick/commit/18df5773b5efbd2c9dc54c9caa021febf486bd22 and https://github.com/ImageMagick/ImageMagick/commit/f1fb7816a60c7c68d7ac037975c5aa95b6dcf8dd for more details.
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