<td>(X)</td>
<td></td>
<td></td>
- <td></td>
+ <td>X</td>
<td></td>
<td></td>
</tr>
<td></td>
<td></td>
<td>X</td>
- <td></td>
+ <td>X</td>
<td></td>
<td></td>
</tr>
<td>(X)</td>
<td></td>
<td>X</td>
- <td></td>
+ <td>X</td>
<td>X</td>
<td></td>
<!--td><a href="#native">FOP native</a> or <a href="#jai">JAI</a>, depending on the subformat. See <a href="#tiff">TIFF</a> for more details.(JIMI also supports TIFF, but this has not been implemented within FOP).</td-->
</tr>
+ <tr>
+ <td><a href="#emf">EMF</a> (Windows Enhanced Metafile)</td>
+ <td>vector (with embedded bitmaps)</td>
+ <td>(X)</td>
+ <td></td>
+ <td></td>
+ <td></td>
+ <td></td>
+ <td></td>
+ </tr>
</table>
<note>"(X)" means restricted support. Please see the details below.</note>
</section>
</p>
</section>
<section id="batik-codecs">
- <title>Batik codecs</title>
+ <title>"Internal" codecs</title>
<p>
- Apache Batik contains codecs for PNG and TIFF access. FOP can use these.
+ Apache XML Graphics Commons contains codecs for PNG and TIFF access. FOP can use these.
</p>
</section>
<section id="imageio">
</p>
</section>
<section id="batik">
- <title>Batik</title>
+ <title>Apache Batik</title>
<p>Current FOP distributions include a distribution of the Apache <a class="fork" href="ext:batik">Batik</a> version 1.6.
It is automatically installed with FOP.
Because Batik's API changes frequently, it is highly recommended that you use the version that ships with FOP, at least when running FOP.</p>
(including GhostScript) will render the EPS correctly.
</li>
</ul>
+ <warning>
+ Please note that the EPS embedding feature has been <strong>deprecated</strong> in the
+ PDF specification version 1.4. You should not use this feature anymore, especially
+ since newer PDF tools don't support embedded EPS files anymore.
+ </warning>
<p>
Other output targets can't be supported at the moment because
FOP lacks a PostScript interpreter. Furthermore, FOP is not able
</section>
<section id="jpeg">
<title>JPEG</title>
- <p>FOP native support of JPEG does not include all variants, especially those containing unusual color lookup tables and color profiles.
-If you have trouble with a JPEG image in FOP, try opening it with an image processing program (such as Photoshop or Gimp) and then saving it.
-Specifying 24-bit color output may also help.
-For the PDF and PostScript renderers most JPEG images can be passed through without decompression.
-User reports indicate that grayscale, RGB, and CMYK color-spaces are all rendered properly.
+ <p>
+ FOP native support of JPEG does not include all variants, especially those containing
+ unusual color lookup tables and color profiles.
+ If you have trouble with a JPEG image in FOP, try opening it with an image processing
+ program (such as Photoshop or Gimp) and then saving it. Specifying 24-bit color output
+ may also help. For the PDF and PostScript renderers most JPEG images can be passed
+ through without decompression. User reports indicate that grayscale, RGB, and
+ CMYK color-spaces are all rendered properly.
</p>
</section>
<section id="png">
<title>PNG</title>
- <p>If using JAI for PNG support, only RGB and RGBA color-spaces are supported for FOP rendering.</p>
+ <p>
+ If using JAI for PNG support, only RGB and RGBA color-spaces are supported for
+ FOP rendering.
+ </p>
+ <p>
+ Transparency is supported but not guaranteed to work with every output format.
+ </p>
</section>
<section id="svg">
<title>SVG</title>
<section id="svg-intro">
<title>Introduction</title>
- <p>FOP uses <a href="#batik">Batik</a> for SVG support.
+ <p>FOP uses <a href="#batik"> Apache Batik</a> for SVG support.
This format can be handled as an <code>fo:instream-foreign-object</code> or in a separate
file referenced with <code>fo:external-graphic</code>.</p>
<note>
Batik's SVG Rasterizer utility may also be used to convert standalone SVG
documents into PDF. For more information please see the
-<a href="http://xml.apache.org/batik/svgrasterizer.html">SVG Rasterizer documentation</a>
+<a href="http://xmlgraphics.apache.org/batik/svgrasterizer.html">SVG Rasterizer documentation</a>
on the Batik site.
</note>
</section>
<p>
The SVG is rendered into PDF by using PDF commands to draw and fill
lines and curves. This means that the graphical objects created with
-this remain as vector graphics.
+this remain as vector graphics. The same applies to PostScript output.
+For other output formats the SVG graphic will be converted to a bitmap
+image.
</p>
<p>
There are a number of SVG things that cannot be converted directly into
PDF. Parts of the graphic such as effects, patterns and images are inserted
-into the PDF as a raster graphic. The resolution of this graphic may not
-be ideal depending on the FOP dpi (72dpi) and the scaling for that graphic.
-We hope to improve this in the future.</p>
+into the PDF as a raster graphic. The resolution of these raster images can
+ be controlled through the "target resolution" setting in the
+ <a href="configuration.html">configuration</a>.</p>
<p>
-Currently transparency is not supported in PDF so many svg images that
-contain effects or graphics with transparent areas will not be displayed
+Currently transparency is limited in PDF so many svg images that
+contain effects or graphics with transparent areas may not be displayed
correctly.
</p>
</section>
<section id="svg-pdf-text">
- <title>Placing SVG Text into PDF</title>
- <p>If possible, Batik will use normal PDF text when inserting text. It does
+ <title>Placing SVG Text into PDF and PostScript</title>
+ <p>If possible, Batik will use normal PDF or PostScript text when inserting text. It does
this by checking if the text can be drawn normally and the font is
supported. This example svg <a href="../dev/svg/text.svg">text.svg</a> /
<!--link href="../dev/svg/text.pdf"-->text.pdf<!--/link-->
shows how various types and effects with text are handled.
Note that tspan and outlined text are not yet implemented.</p>
<p>
-Otherwise, text is converted and drawn as a set of shapes by batik, using the stroking text painter.
+Otherwise, text is converted and drawn as a set of shapes by Batik, using the stroking text painter.
This means that a typical character will
have about 10 curves (each curve consists of at least 20 characters).
-This can make the pdf files large and when the pdf is viewed the
-viewer does not normally draw those fine curves very well (turning on
-Smooth Line Art in the Acrobat preferences will fix this).
-If the text is inserted into the PDF using the inbuilt text commands
-for PDF it will use a single character.
+This can make the output files large and when it is viewed the
+viewer may not normally draw those fine curves very well (In Adobe Acrobat, turning on
+"Smooth Line Art" in the preferences will fix this).
+If the text is inserted into the output file using the inbuilt text commands
+it will use a single character.
</p>
- <p>Note that because SVG text can be rendered as either text or a vector graphic, you may need to consider settings in your viewer for both.
-The Acrobat viewer has both "smooth line art" and "smooth text" settings that may need to be set for SVG images to be displayed nicely on your screen (see Edit / Preferences / Display).
-This setting will not affect the printing of your document, which should be OK in any case, but will only affect the quality of the screen display.</p>
+ <p>
+ Note that because SVG text can be rendered as either text or a vector graphic, you
+ may need to consider settings in your viewer for both. The Acrobat viewer has both
+ "smooth line art" and "smooth text" settings that may need to be set for SVG images
+ to be displayed nicely on your screen (see Edit / Preferences / Display).
+ This setting will not affect the printing of your document, which should be OK in
+ any case, but will only affect the quality of the screen display.</p>
</section>
<section id="svg-scaling">
<title>Scaling</title>
- <p>Currently, SVG images are rendered with the dimensions specified <em>in the SVG file</em>, within the viewport specified in the fo:external-graphic element.
-For everything to work properly, the two should be equal.
-The SVG standard leaves this issue as an implementation detail.
-FOP will probably implement a scaling mechanism in the future.</p>
+ <p>
+ Currently, SVG images are rendered with the dimensions specified <em>in the SVG
+ file</em>, within the viewport specified in the fo:external-graphic element.
+ For everything to work properly, the two should be equal. The SVG standard leaves
+ this issue as an implementation detail. FOP will probably implement a scaling
+ mechanism in the future.
+ </p>
+ <p>
+ If you use pixels to specify the size of an SVG graphic the "source resolution" setting
+ in the <a href="configuration.html">configuration</a> will be used to determine the
+ size of a pixel. The use of pixels to specify sizes is discouraged as they may
+ be interpreted differently in different environments.
+ </p>
</section>
<section id="svg-problems">
<title>Known Problems</title>
<ul>
<li>
-soft mask transparency is combined with white so that it looks better
+Soft mask transparency is combined with white so that it looks better
on pdf 1.3 viewers but this causes the soft mask to be slightly lighter
-or darker on pdf 1.4 viewers
+or darker on pdf 1.4 viewers.
</li>
<li>
-there is some problem with a gradient inside a pattern causing a pdf
-error when viewed in acrobat 5
+There is some problem with a gradient inside a pattern causing a PDF
+error when viewed in acrobat 5.
</li>
<li>
-text is not always handled correctly, it may select the wrong font
-especially if characters have multiple fonts in the font list
+Text is not always handled correctly, it may select the wrong font
+especially if characters have multiple fonts in the font list.
</li>
<li>
-more pdf text handling could be implemented
+More PDF text handling could be implemented.
It could draw the string using the attributed character iterator
to handle tspans and other simple changes of text.
</li>
<li>
-JPEG images are not inserted directly into the pdf document
+JPEG images are not inserted directly into the pdf document.
This area has not been implemented yet since the appropriate
-method in batik is static
+method in batik is static.
</li>
<li>
Uniform transparency for images and other svg elements that are converted
</section>
<section id="tiff">
<title>TIFF</title>
- <p>FOP-native TIFF support is limited to PDF and PostScript output only. Also, according to user reports, FOP's native support for TIFF is limited to images with the following characteristics (all must be true for successful rendering):</p>
+ <p>
+ FOP-native TIFF support is limited to PDF and PostScript output only. Also,
+ according to user reports, FOP's native support for TIFF is limited to images with the
+ following characteristics (all must be true for successful rendering):
+ </p>
<ul>
<li>single channel images (i.e., bi-level and grayscale only)</li>
<li>uncompressed images, or images using CCITT T.4, CCITT T.6, or JPEG compression</li>
<li>images using white-is-zero encoding in the TIFF PhotometricInterpretation tag</li>
</ul>
+ <note>
+ Native support in this case means that the images can be embedded into the output format
+ without decoding it.
+ </note>
<p><em>JAI:</em> Supports RGB and RGBA only for FOP rendering.</p>
</section>
+ <section id="emf">
+ <title>EMF</title>
+ <p>Windows Enhanced Metafiles (EMF) are only supported in RTF output.</p>
+ </section>
<section id="resolution">
<title>Graphics Resolution</title>
- <p>Some bitmapped image file formats store a dots-per-inch (dpi) or other resolution value. Since PDF and most output formats do not have a concept of resolution, but only of absolute image units (i.e. pixels) FOP ignores the resolution values as well. Instead, FOP uses the dimensions of the image as specified in the fo:external-graphic element to render the image:</p>
- <ul>
- <li>If no dimensions are given, FOP uses a default value of 72 dpi to compute the graphic's dimensions. For example, suppose a graphic 300 pixels wide and 400 pixels high. FOP will render the graphic at 4.167 inches wide, 5.555 inches high, with an apparent resolution of 72 dpi.</li>
- <li>If only one dimension is given, FOP by default uses the same aspect ratio to compute the other dimension (to avoid the appearance of stretching). For example, suppose a graphic 300 pixels wide and 400 pixels high, for which content-width = ".5in". FOP will compute the content-height = .667 inches, and will render the graphic at that size, with an apparent resolution of 600 dpi.</li>
- <li>If both dimensions are given, FOP simply renders the image in that space. For example, suppose a graphic 300 pixels wide and 400 pixels high, for which content-width = "3in" and content-height = "4in". FOP will render the graphic at that size, with an apparent resolution of 100 dpi.</li>
- </ul>
- <p>If you need a higher apparent output resolution for bitmapped images, first make sure that at least one dimension of the image is defined in your XSL-FO input. Apart from that, resolution problems are in the image file itself, and must be corrected there: use or create a higher-resolution image file.</p>
- <note>The explanation above describes only the basic default behavior. There are other attributes of the fo:external-graphic element that can affect the behavior described above.</note>
+ <p>
+ Some bitmapped image file formats store a dots-per-inch (dpi) or other resolution
+ values. FOP tries to use this resolution information whenever possible to determine
+ the image's intrinsic size. This size is used during the layout process when it is not
+ superceeded by an explicit size on fo:external-graphic (content-width and content-height
+ properties).
+ </p>
+ <p>
+ Please note that not all images contain resolution information. If it's not available
+ 72 dpi is assumed (the default resolution of PDF and PostScript).
+ </p>
+ <p>
+ Bitmap images are generally embedded into the output format at their original resolution
+ (as is). No resampling of the image is performed. Explicit resampling is on our wishlist,
+ but hasn't been implemented, yet. Bitmaps included in SVG graphics may be resampled to
+ the resolution specified in the "target resolution" setting in the
+ <a href="configuration.html">configuration</a> if SVG filters are applied. This can be
+ used as a work-around to resample images in FO documents.
+ </p>
</section>
<section id="caching">
<title>Image caching</title>
<p>
- FOP caches images between runs. The URL is used as a key to identify images which means that when
- a particular URL appears again, the image is taken from the cache. If you have a servlet that
- generates a different image each time it is called with the same URL you need to use a constantly
+ FOP caches images between runs. There is one cache per FopFactory instance. The URI is
+ used as a key to identify images which means that when a particular URI appears again,
+ the image is taken from the cache. If you have a servlet that generates a different
+ image each time it is called with the same URL you need to use a constantly
changing dummy parameter on the URL to avoid caching.
</p>
<p>
- The image cache has been improved considerably in the redesigned code. Therefore, a resetCache() method
- has become unnecessary. If you still experience OutOfMemoryErrors, please notify us.
+ The image cache has been improved considerably in the redesigned code. Therefore, a
+ resetCache() method like in earlier versions of FOP has become unnecessary. If you
+ still experience OutOfMemoryErrors, please notify us.
</p>
</section>
</body>
projects / xmlgraphics-fop.git / commitdiff