D19513: Fix ibeam and underline cursor rendering

[Wolfgang Bauer]

wbauer created this revision.
wbauer added a reviewer: Konsole.
wbauer added a project: Konsole.
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REVISION SUMMARY
  Since anti-aliasing was enabled in the painter, coordinates need to be shifted half a pixel so that they align with the pixel grid, otherwise the result gets "blurred" due to the anti-aliasing.
  And as parts of the blurred shape leak outside the cursor rectangle, this also leaves artifacts when the cursor moves as these parts are not cleared.
  
  This is basically the same as https://phabricator.kde.org/R319:e7085310d6d594823d0ed491fa8bdbd99dec4932 for the standard block cursor.
  
  BUG: 402589

TEST PLAN
  - Switch cursor shape to "I-Beam" or "Underline" in the "Advanced" profile settings
  
  The cursors are a single line again now, before they were blurred by anti-aliasing.
  
  Screenshots:
  Before:
  F6656366: ibeam-before.png <https://phabricator.kde.org/F6656366>
  F6656370: underline-before.png <https://phabricator.kde.org/F6656370>
  
  After:
  F6656371: ibeam-after.png <https://phabricator.kde.org/F6656371>
  F6656373: underline-after.png <https://phabricator.kde.org/F6656373>
  
  Also, there are no more artifacts when the cursor is moved.

REPOSITORY
  R319 Konsole

REVISION DETAIL
  https://phabricator.kde.org/D19513

AFFECTED FILES
  src/TerminalDisplay.cpp

To: wbauer, #konsole
Cc: konsole-devel, gennad, maciejn, thsurrel, ngraham, maximilianocuria, hindenburg
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