United StatesChange Country, Oracle Worldwide Web Sites Communities I am a... I want to...
Bug ID: 6656651 Windows Look and Feel LCD glyph images have some differences from native applications.
6656651 : Windows Look and Feel LCD glyph images have some differences from native applications.

Details
Type:
Bug
Submit Date:
2008-01-29
Status:
Closed
Updated Date:
2010-04-02
Project Name:
JDK
Resolved Date:
2008-02-14
Component:
client-libs
OS:
generic
Sub-Component:
2d
CPU:
generic
Priority:
P3
Resolution:
Fixed
Affected Versions:
6
Fixed Versions:
6u10

Related Reports
Backport:
JDK-2162039 - Windows Look and Feel LCD glyph images have some differences from native applications.
Relates:
JDK-6685312 - Unscaled advances for LCD Text in 6u10 beta
Relates:
JDK-6997947 - Degradation of VALUE_TEXT_ANTIALIAS_LCD_HRGB rendering from 1.6.0_1 to 1.6.0_22
Relates:
JDK-6591278 - Wrong rendering of transformed fonts on Windows with Java 6
Relates:
JDK-6679904 - JDK6u10 beta on windows: \u200bc not rendered properly in LCD text mode.

Sub Tasks

Description
The Java 2D LCD glyph rasterisation is not the same as that of the Microsoft
Cleartype rasteriser. Some of the resulting differences are observable on Vista and XP
in applications which utilise the Windows L&F.

Comments
EVALUATION

This can be fixed by asking GDI to perform the rasterisation of glyphs,
then caching these glyphs in the same way as now. This avoids disruption to the
various 2D rendering pipelines, particularly its hardware acceleration
architecture.
This has been verified with software and D3D and OpenGL pipelines,
and with SwingSet and Font2DTest.
Verification has also included complex scripts which requires glyph
positioning.
Glyph advance is still obtained from the JDK rasteriser which
ensures that in the cases of fractional metrics, or algorithmically
styled text, we maintain metrics compatibility. For integer metrics
and no algorithmic styling JDK and GDI already agree for 99.75% of
all glyphs, with only some obscure cases differing likely due to rounding.
Some of the benefits of this approach are behavioural and
metric compatibility with the existing code.
2008-01-29


Hardware and Software, Engineered to Work Together