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authorAlbrecht Schlosser <albrechts.fltk@online.de>2016-07-24 08:55:02 +0000
committerAlbrecht Schlosser <albrechts.fltk@online.de>2016-07-24 08:55:02 +0000
commita633de6461f5f494d105c957d6efd43dadb193d4 (patch)
tree3e20ce6892235d6d9a19708f02408cf712875c91 /src
parent54dcf145feb39f4eb2e9cd78de2ce469acd3e28c (diff)
Doc changes: set fl_font before fl_measure() (STR #3243)
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3-porting@11848 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
Diffstat (limited to 'src')
-rw-r--r--src/fl_draw.cxx14
1 files changed, 9 insertions, 5 deletions
diff --git a/src/fl_draw.cxx b/src/fl_draw.cxx
index bf02f9d8e..d6e184002 100644
--- a/src/fl_draw.cxx
+++ b/src/fl_draw.cxx
@@ -3,7 +3,7 @@
//
// Label drawing code for the Fast Light Tool Kit (FLTK).
//
-// Copyright 1998-2011 by Bill Spitzak and others.
+// Copyright 1998-2016 by Bill Spitzak and others.
//
// This library is free software. Distribution and use rights are outlined in
// the file "COPYING" which should have been included with this file. If this
@@ -118,7 +118,7 @@ static const char* expand_text_(const char* from, char*& buf, int maxbuf, double
Also word-wrap if width exceeds maxw.
Returns a pointer to the start of the next line of characters.
Sets n to the number of characters put into the buffer.
- Sets width to the width of the string in the current font.
+ Sets width to the width of the string in the \ref drawing_fl_font "current font".
*/
const char*
fl_expand_text(const char* from, char* buf, int maxbuf, double maxw, int& n,
@@ -343,9 +343,13 @@ void fl_draw(
fl_draw() function with \p align parameter. If the incoming \p w
is non-zero it will wrap to that width.
- The 'current font' is used to do the width/height calculations,
- so unless its value is known at the time fl_measure() is called,
- it is advised to first set the current font with fl_font().
+ The \ref drawing_fl_font "current font" is used to do the width/height
+ calculations, so unless its value is known at the time fl_measure() is
+ called, it is advised to first set the current font with fl_font().
+ With event-driven GUI programming you can never be sure which
+ widget was exposed and redrawn last, nor which font it used.
+ If you have not called fl_font() explicitly in your own code,
+ the width and height may be set to unexpected values, even zero!
\b Note: In the general use case, it's a common error to forget to set
\p w to 0 before calling fl_measure() when wrap behavior isn't needed.