Text is blurry when you magnify the text in Windows 7 or Windows Server 2008 R2

Gäller för: Windows Server 2008 R2 Service Pack 1Windows Server 2008 R2 DatacenterWindows Server 2008 R2 Enterprise Mer

Symptoms


Consider the following scenario:

  • You log on to a computer locally or by using Remote Desktop Protocol (RDP) in Windows 7 Service Pack 1 (SP1) or Windows Server 2008 R2 SP1.
  • You use a window magnification tool to magnify part of the screen at a high zoom rate (such as over 900%). 
In this scenario, the text becomes blurry.

How to obtain this hotfix


To resolve this issue, we have released hotfixes for Windows 7 SP1 or Windows Server 2008 R2 SP1.

Hotfix for Windows 7 or Windows Server 2008 R2

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem.

If the hotfix is available for download, there is a "Hotfix Download Available" section at the top of this Knowledge Base article. If this section does not appear, submit a request to Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft website: Note The "Hotfix Download Available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

There are no prerequisites for installing this hotfix.

Registry information

To use the hotfix in this package, you do not have to make any changes to the registry.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

More Information


For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates.

Cause

This issue occurs because the following setting can affect the text rendering:

  • Magnification APIs that are used by the magnifier uses GDI+ InterpolationModeHighQualityBilinear interpolation mode for rendering. 

    Note After you apply this hotfix, magnification APIs uses the default GDI+ Interpolation mode.

  • Windows 7 introduces some changes in ClearType and grayscale technologies. When these modifications try to improve the font rendering and reading experience, text appears blurry when you use a high screen magnification zoom. To work around this issue, disable the following settings:

    Note For more information about the changes in ClearType and grayscale technologies, go to the following Microsoft website:

    • Disable the Turn On ClearType option by clicking the Adjust ClearType text link in the Appearance and Personalization window in Control Panel.
    • Disable the following options:
      • Disable all the options under the Visual Effects tab in the Performance Settings window under the Advanced tab in the System Properties window for the System setting in Control Panel.
      • When you use a Remote Desktop Protocol (RDP) connection, disable all performance options under the Experience tab.
      • Disable the ClearType usage in some applications. For example, disable the Always use ClearType for HTML option under the Adavanced tab in Internet Options in Microsoft Internet Explorer 8.

Status


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.