From fd2623102a9bad31258a0ef31ce6a2972ae6ddad Mon Sep 17 00:00:00 2001
From: Neil <nyamatongwe@gmail.com>
Date: Wed, 2 Feb 2022 14:25:51 +1100
Subject: Feature [feature-requests:#1427] Add multithreaded layout which
 improves performance significantly for very wide lines.

---
 doc/ScintillaDoc.html | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

(limited to 'doc/ScintillaDoc.html')

diff --git a/doc/ScintillaDoc.html b/doc/ScintillaDoc.html
index 58e8da944..932d26de8 100644
--- a/doc/ScintillaDoc.html
+++ b/doc/ScintillaDoc.html
@@ -7449,6 +7449,8 @@ sptr_t CallScintilla(unsigned int iMessage, uptr_t wParam, sptr_t lParam){
      <a class="message" href="#SCI_GETLAYOUTCACHE">SCI_GETLAYOUTCACHE &rarr; int</a><br />
      <a class="message" href="#SCI_SETPOSITIONCACHE">SCI_SETPOSITIONCACHE(int size)</a><br />
      <a class="message" href="#SCI_GETPOSITIONCACHE">SCI_GETPOSITIONCACHE &rarr; int</a><br />
+     <a class="message" href="#SCI_SETLAYOUTTHREADS">SCI_SETLAYOUTTHREADS(int threads)</a><br />
+     <a class="message" href="#SCI_GETLAYOUTTHREADS">SCI_GETLAYOUTTHREADS &rarr; int</a><br />
      <a class="message" href="#SCI_LINESSPLIT">SCI_LINESSPLIT(int pixelWidth)</a><br />
      <a class="message" href="#SCI_LINESJOIN">SCI_LINESJOIN</a><br />
      <a class="message" href="#SCI_WRAPCOUNT">SCI_WRAPCOUNT(line docLine) &rarr; line</a><br />
@@ -7687,6 +7689,21 @@ sptr_t CallScintilla(unsigned int iMessage, uptr_t wParam, sptr_t lParam){
      so that their layout can be determined more quickly if the run recurs.
      The size in entries of this cache can be set with <code>SCI_SETPOSITIONCACHE</code>.</p>
 
+    <p><b id="SCI_SETLAYOUTTHREADS">SCI_SETLAYOUTTHREADS(int threads)</b><br />
+     <b id="SCI_GETLAYOUTTHREADS">SCI_GETLAYOUTTHREADS &rarr; int</b><br />
+     The time taken to measure text runs on wide lines can be improved by performing the task
+     concurrently on multiple threads when
+     <a class="seealso" href="#SCI_SUPPORTSFEATURE">SC_SUPPORTS_THREAD_SAFE_MEASURE_WIDTHS</a>
+     is available.
+     This can be a dramatic improvement - a 4 core processor is often able to reduce text layout time to just over one
+     quarter of the single-threaded time.</p>
+     <p>The default is to use just the main thread but applications may call <code>SCI_SETLAYOUTTHREADS</code>
+     to specify the maximum number of threads to use.
+     The number of threads is limited to the hardware concurrency of the system -
+     for a 4 core processor with hyper-threading that would be 8.
+     If an application just wants maximum concurrency then call with a large number
+     <code>SCI_SETLAYOUTTHREADS(1000)</code> and that will be reduced to a reasonable value.</p>
+
     <p><b id="SCI_LINESSPLIT">SCI_LINESSPLIT(int pixelWidth)</b><br />
      Split a range of lines indicated by the target into lines that are at most pixelWidth wide.
      Splitting occurs on word boundaries wherever possible in a similar manner to line wrapping.
-- 
cgit v1.2.3