commit 8edadee1458192f4fc34ffc2a9aaff878b179257
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date: Sun Jul 23 12:39:26 2017 +0200
Update the painting process documentation
---
development/PAINTING_ANALYSIS | 44 +++++++++++++---------------------------
1 files changed, 14 insertions(+), 30 deletions(-)
diff --git a/development/PAINTING_ANALYSIS b/development/PAINTING_ANALYSIS
index e53b4b2..9d62593 100644
--- a/development/PAINTING_ANALYSIS
+++ b/development/PAINTING_ANALYSIS
@@ -67,31 +67,11 @@ drawing from metrics.
Other changes are only clean-ups.
** When a paragraph ends with a newline, compute correctly the height of the
extra row.
-** Rewrite TextMetrics::editXY, checkInsetHit using row information
(getPosNearX)?
-
- The helper version should return a Row::Element instead of an InsetTable.
-
-** Set inset position during metrics phase
-
-In order to do that, a no-paint drawing will be initiated after every
-redoParagraph. This code path will need to be made as fast as possible.
-
-Effect: avoid depending on actual drawing having taken place. In turn,
-it will allow to do drawing on paint events, like any reasonable
-application would do.
-
** Cleanup after complete metrics
Then the following can be done:
+ remove hack in InsetMathNest::drawSelection
- + remove painting when not inside in drawParagraph
+ remove Cursor::inCoordCache?
-** Paint directly to screen
-
-Instead of using an intermediary pixmap. I have no idea of how
-difficult it will prove.
-One benefit will be that subpixel aliasing will work again (#9972)
-
** Merging bv::updateMetrics and tm::metrics
While the full metrics computation tries hard to limit the number of
@@ -107,19 +87,19 @@ necessary to break the whole contents to know the width of
the cell.
* Description of current drawing mechanism
-** Two stage drawing
+** Three-stage drawing
-There are two parts to drawing the work area:
+There are three parts to drawing the work area:
+ the metrics phase computes the size of insets and breaks the
paragraphs into rows. It stores the dimension of insets (both
normal and math) in bv::coordCache.
- + the drawing phase draws the contents and caches the inset
- positions. Since the caching of positions is useful in itself,
- there is a provision for drawing "without" drawing when the only
- thing we want is to cache inset positions
- (Painter::setDrawingEnabled).
+ + the nodraw drawing phase paints the screen (see below) with a null
+ painter. The only useful effect is to store the inset positions.
+
+ + an update() signal is sent. This in turn will trigger a paint
+ event, and the actual screen painting will happen then.
The machinery is controlled via bv::processUpdateFlags. This method is
called at the end of bv::mouseEventDispatch and in
@@ -145,7 +125,7 @@ update flag is Update::None.
** Metrics computation
This is triggered by bv::updateMetrics, which calls tm::redoParagraph for
-all visible paragraphs. Paragraphs above or below the screen (needed
+all visible paragraphs. Some Paragraphs above or below the screen (needed
for page up/down) and computed as needed.
tm::redoParagraph will call Inset::metrics for each inset. In the case
@@ -155,8 +135,9 @@ all the paragraphs of the inset.
** Drawing the work area.
-This is done in bv::draw. This method is triggered mainly by
-Buffer::changed, which draws all the work areas that show the given buffer.
+This is done in bv::draw. This method is triggered by a paint event,
+mainly called through Buffer::changed, which draws all the work areas
+that show the given buffer.
Note that, When Buffer::changed is called outside of
bv::processUpdateFlags, it is not clear whether the update strategy
@@ -186,3 +167,6 @@ The action depends on the update strategy:
+ SingleParUpdate: only tries to repaint current paragraph in a way
that is not yet very clear to me.
+
+BufferView::draw can also be called with a null painter from
+BufferView::updateMetrics().
