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This patch serves two purposes. First, it factors out the heavy part of the cairo_scaled_font_text_to_glyphs() routine thus allowing GCC to better optimize the cache cleanup loop. Keeping the look-up table indices in a separate array speeds up array initialization even further. Second, this patch introduces a shortcut for the case when the string to be rendered consists of a single character. In this case, caching is not necessary at all. We have a benchmark that uses Cairo to render a large amount of random strings of consisting of printable ASCII characters. Below are Oprofile results collected while running this benchmark. It is easy to see that the heavy part becomes noticeably lighter. Before: Profiling through timer interrupt samples % app name symbol name 198755 13.5580 libcairo.so.2.10907.0 cairo_scaled_font_text_to_glyphs 88580 6.0424 libcairo.so.2.10907.0 _cairo_scaled_glyph_lookup 81127 5.5340 libcairo.so.2.10907.0 _cairo_hash_table_lookup 68186 4.6513 libcairo.so.2.10907.0 cairo_scaled_font_glyph_extents 47145 3.2160 libcairo.so.2.10907.0 _composite_glyphs_via_mask 46327 3.1602 libcairo.so.2.10907.0 _cairo_scaled_font_glyph_device_extents 44817 3.0572 libcairo.so.2.10907.0 _composite_glyphs 40431 2.7580 libcairo.so.2.10907.0 .plt After (note that cairo_scaled_font_text_to_glyphs_internal_single() was inlined): Profiling through timer interrupt samples % app name symbol name 107264 7.6406 libcairo.so.2.10907.0 cairo_scaled_font_text_to_glyphs_internal_multiple 87888 6.2604 libcairo.so.2.10907.0 _cairo_scaled_glyph_lookup 79011 5.6281 libcairo.so.2.10907.0 _cairo_hash_table_lookup 71723 5.1090 libcairo.so.2.10907.0 cairo_scaled_font_glyph_extents 48084 3.4251 libcairo.so.2.10907.0 _composite_glyphs_via_mask 46636 3.3220 libcairo.so.2.10907.0 _cairo_scaled_font_glyph_device_extents 44740 3.1869 libcairo.so.2.10907.0 _composite_glyphs 42472 3.0254 libc-2.8.so _int_malloc 39194 2.7919 libcairo.so.2.10907.0 _cairo_gstate_transform_glyphs_to_backend 38614 2.7506 libcairo.so.2.10907.0 .plt 37063 2.6401 libcairo.so.2.10907.0 _cairo_ft_ucs4_to_index 36856 2.6253 libc-2.8.so random 36376 2.5911 libcairo.so.2.10907.0 _cairo_scaled_glyphs_equal 34545 2.4607 libcairo.so.2.10907.0 cairo_matrix_transform_point 31690 2.2573 libc-2.8.so malloc 29395 2.0939 libcairo.so.2.10907.0 _cairo_matrix_is_identity 26142 1.8621 libcairo.so.2.10907.0 _cairo_utf8_to_ucs4 24406 1.7385 libc-2.8.so free 24059 1.7138 libcairo.so.2.10907.0 cairo_scaled_font_text_to_glyphs [ickle: slightly amended for stylistic consistency.] |
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| boilerplate | ||
| build | ||
| doc | ||
| perf | ||
| src | ||
| test | ||
| util | ||
| .gitignore | ||
| acinclude.m4 | ||
| AUTHORS | ||
| autogen.sh | ||
| BIBLIOGRAPHY | ||
| BUGS | ||
| cairo-version.h | ||
| CODING_STYLE | ||
| configure.ac | ||
| COPYING | ||
| COPYING-LGPL-2.1 | ||
| COPYING-MPL-1.1 | ||
| HACKING | ||
| INSTALL | ||
| Makefile.am | ||
| Makefile.win32 | ||
| NEWS | ||
| PORTING_GUIDE | ||
| README | ||
| README.win32 | ||
| RELEASING | ||
Cairo - Multi-platform 2D graphics library
http://cairographics.org
What is cairo
=============
Cairo is a 2D graphics library with support for multiple output
devices. Currently supported output targets include the X Window
System, quartz, win32, and image buffers, as well as PDF, PostScript,
and SVG file output. Experimental backends include OpenGL, XCB, BeOS,
OS/2, and DirectFB.
Cairo is designed to produce consistent output on all output media
while taking advantage of display hardware acceleration when available
(for example, through the X Render Extension).
The cairo API provides operations similar to the drawing operators of
PostScript and PDF. Operations in cairo include stroking and filling
cubic Bézier splines, transforming and compositing translucent images,
and antialiased text rendering. All drawing operations can be
transformed by any affine transformation (scale, rotation, shear,
etc.).
Cairo has been designed to let you draw anything you want in a modern
2D graphical user interface. At the same time, the cairo API has been
designed to be as fun and easy to learn as possible. If you're not
having fun while programming with cairo, then we have failed
somewhere---let us know and we'll try to fix it next time around.
Cairo is free software and is available to be redistributed and/or
modified under the terms of either the GNU Lesser General Public
License (LGPL) version 2.1 or the Mozilla Public License (MPL) version
1.1.
Where to get more information about cairo
=========================================
The primary source of information about cairo is:
http://cairographics.org/
The latest versions of cairo can always be found at:
http://cairographics.org/download
Documentation on using cairo and frequently-asked questions:
http://cairographics.org/documentation
http://cairographics.org/FAQ
Mailing lists for contacting cairo users and developers:
http://cairographics.org/lists
Roadmap and unscheduled things to do, (please feel free to help out):
http://cairographics.org/roadmap
http://cairographics.org/todo
Dependencies
============
The set of libraries needed to compile cairo depends on which backends
are enabled when cairo is configured. So look at the list below to
determine which dependencies are needed for the backends of interest.
For the surface backends, we have both "supported" and "experimental"
backends. Further, the supported backends can be divided into the
"standard" backends which can be easily built on any platform, and the
"platform" backends which depend on some underlying platform-specific
system, (such as the X Window System or some other window system).
As an example, for a standard Linux build, (with image, png, pdf,
PostScript, svg, and xlib surface backends, and the freetype font
backend), the following sample commands will install necessary
dependencies:
Debian (and similar):
apt-get install libpng12-dev libz-dev libxrender-dev libfontconfig1-dev
Fedora (and similar):
yum install libpng-devel zlib-devel libXrender-devel fontconfig-devel
(Those commands intentionally don't install pixman from a distribution
package since if you're manually compiling cairo, then you likely want
to grab pixman from the same place at the same time and compile it as
well.)
Supported, "standard" surface backends
------------------------------------
image backend (required)
------------------------
pixman >= 0.12.0 http://cairographics.org/releases
png support (can be left out if desired, but many
----------- applications expect it to be present)
libpng http://www.libpng.org/pub/png/libpng.html
pdf backend
-----------
zlib http://www.gzip.org/zlib
postscript backend
------------------
zlib http://www.gzip.org/zlib
svg backend
-----------
[none]
Supported, "platform" surface backends
-----------------------------------
xlib backend
------------
X11 http://freedesktop.org/Software/xlibs
xlib-xrender backend
--------------------
Xrender >= 0.6 http://freedesktop.org/Software/xlibs
quartz backend
--------------
MacOS X >= 10.4 with Xcode >= 2.4
win32 backend
-------------
Microsoft Windows 2000 or newer[*].
Font backends (required to have at least one)
---------------------------------------------
freetype font backend
---------------------
freetype >= 2.1.9 http://freetype.org
fontconfig http://fontconfig.org
quartz-font backend
-------------------
MacOS X >= 10.4 with Xcode >= 2.4
win32 font backend
------------------
Microsoft Windows 2000 or newer[*].
[*] The Win32 backend should work on Windows 2000 and newer
(excluding Windows Me.) Most testing has been done on
Windows XP. While some portions of the code have been
adapted to work on older versions of Windows, considerable
work still needs to be done to get cairo running in those
environments.
Cairo can be compiled on Windows with either the gcc
toolchain (see http://www.mingw.org) or with Microsoft
Visual C++. If the gcc toolchain is used, the standard
build instructions using configure apply, (see INSTALL).
If Visual C++ is desired, GNU make is required and
Makefile.win32 can be used via 'make -f Makefile.win32'.
The compiler, include paths, and library paths must be set
up correctly in the environment.
MSVC versions earlier than 7.1 are known to miscompile
parts of cairo and pixman, and so should be avoided. MSVC
7.1 or later, including the free Microsoft Visual Studio
Express editions, produce correct code.
Experimental surface backends
-----------------------------
xcb backend
-----------
XCB http://xcb.freedesktop.org
beos backend
------------
No dependencies in itself other than an installed BeOS system, but cairo
requires a font backend. See the freetype dependency list.
os2 backend
-----------
Cairo should run on any recent version of OS/2 or eComStation, but it
requires a font backend. See the freetype dependency list. Ready to use
packages and developer dependencies are available at Netlabs:
ftp://ftp.netlabs.org/pub/cairo
Compiling
=========
See the INSTALL document for build instructions.
History
=======
Cairo was originally developed by Carl Worth <cworth@cworth.org> and
Keith Packard <keithp@keithp.com>. Many thanks are due to Lyle Ramshaw
without whose patient help our ignorance would be much more apparent.
Since the original development, many more people have contributed to
cairo. See the AUTHORS files for as complete a list as we've been able
to compile so far.