[gimp-help/gimp-help-2-10] Fix #232: Newsprint documentation referenced the old plugin.
- From: Jacob Boerema <jboerema src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [gimp-help/gimp-help-2-10] Fix #232: Newsprint documentation referenced the old plugin.
- Date: Sat, 24 Sep 2022 19:00:08 +0000 (UTC)
commit d239e1aac4cdafd082411aeb02e4abe09f573a90
Author: Jacob Boerema <jgboerema gmail com>
Date: Sat Sep 24 14:59:41 2022 -0400
Fix #232: Newsprint documentation referenced the old plugin.
The Newsprint filter was changed to a GEGL filter since 2.10, but the
documentation was never updated and there were considerable differences.
This commit updates the documentation to reflect the current plug-in,
including updated images and one removed image that seemed to be specific
to the old plugin.
images/C/filters/distort/newsprint.png | Bin 26456 -> 28846 bytes
.../C/filters/examples/distort-taj-newsprint.jpg | Bin 94909 -> 87627 bytes
src/filters/distort.xml | 4 +-
src/filters/distort/newsprint.xml | 236 ++++++++++-----------
src/glossary/glossary.xml | 2 +-
5 files changed, 111 insertions(+), 131 deletions(-)
---
diff --git a/images/C/filters/distort/newsprint.png b/images/C/filters/distort/newsprint.png
index bc86d3ab7..750bfe9a8 100644
Binary files a/images/C/filters/distort/newsprint.png and b/images/C/filters/distort/newsprint.png differ
diff --git a/images/C/filters/examples/distort-taj-newsprint.jpg
b/images/C/filters/examples/distort-taj-newsprint.jpg
index 603898912..150ace0ca 100644
Binary files a/images/C/filters/examples/distort-taj-newsprint.jpg and
b/images/C/filters/examples/distort-taj-newsprint.jpg differ
diff --git a/src/filters/distort.xml b/src/filters/distort.xml
index 138b52ea5..663340f6b 100644
--- a/src/filters/distort.xml
+++ b/src/filters/distort.xml
@@ -2,7 +2,7 @@
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
"http://www.docbook.org/xml/4.3/docbookx.dtd";>
<!-- section history:
-
+
-->
<sect1 xmlns:xi="http://www.w3.org/2001/XInclude"; id="filters-distort">
<title>Distort Filters</title>
@@ -21,6 +21,7 @@
<xi:include href="distort/lens-distortion.xml"/>
<!--<xi:include href="distort/kaleidoscope.xml"/>-->
<xi:include href="distort/mosaic.xml"/>
+ <xi:include href="distort/newsprint.xml"/>
<xi:include href="distort/polarcoords.xml"/>
<xi:include href="distort/ripple.xml"/>
<xi:include href="distort/shift.xml"/>
@@ -32,7 +33,6 @@
<xi:include href="distort/wind.xml"/>
<xi:include href="distort/curve_bend.xml"/>
<xi:include href="distort/emboss-legacy.xml"/>
- <xi:include href="distort/newsprint.xml"/>
<xi:include href="distort/pagecurl.xml"/>
<!-- Suppr
diff --git a/src/filters/distort/newsprint.xml b/src/filters/distort/newsprint.xml
index de48fc7bf..97b3f089e 100644
--- a/src/filters/distort/newsprint.xml
+++ b/src/filters/distort/newsprint.xml
@@ -7,7 +7,7 @@
2005-12-07 replaced <simplesect> by <sect3> by lexa
2005-09-09 de added by axel.wernicke
-->
-<sect2 id="plug-in-newsprint">
+<sect2 xmlns:xi="http://www.w3.org/2001/XInclude"; id="gimp-filter-newsprint">
<title>Newsprint</title>
<indexterm>
@@ -38,15 +38,21 @@
fileref="images/filters/examples/distort-taj-newsprint.jpg"/>
</imageobject>
<caption>
- <para>Filter <quote>Newsprint</quote> applied</para>
+ <para>
+ Filter <quote>Newsprint</quote> applied using RGB color mode,
+ PSSquare pattern for all channels, red period 6, green period 8,
+ blue period 10, angle 15 for all channels.
+ </para>
</caption>
</mediaobject>
</figure>
<para>
- This filter halftones the image using a clustered-dot dither. Halftoning
- is the process of rendering an image with multiple levels of grey or
- color (i.e. a continuous tone image) on a device with fewer tones;
+ This filter performs digital halftoning with optional modulations.
+ Halftoning is the process of rendering an image with multiple levels of
+ gray or color (i.e. a continuous tone image) on a device with fewer tones;
often a bi-level device such as a printer or typesetter.
+ Be aware that Newsprint is not a filter for generating half-tone screens
+ for print, but for simulating the appearance of printing with them.
</para>
<para>
The basic premise is to trade off resolution for greater apparent tone
@@ -59,30 +65,18 @@
spatial resolution is lost.
</para>
<para>
- This filter uses a clustered-dot ordered dither, which reduces the
- resolution of the image by converting cells into spots which grow or
- shrink according to the intensity that cell needs to represent.
- </para>
- <para>
- Imagine a grid super-imposed on the original image. The image is
+ Imagine a grid super-imposed on the original image. The image is
divided into cells by the grid - each cell will ultimately hold a single
spot made up of multiple output pixels in order to approximate the
- darkness of the original image in that cell.
- </para>
- <para>
- Obviously, a large cell size results in a heavy loss in resolution! The
- spots in the cells typically start off as circles, and grow to be
- diamond shaped. This change in shape is controlled by a
- <guilabel>Spot function</guilabel>. By using different spot
- functions, the evolution in the shape of the spots as the cell goes from
- fully black to fully white may be controlled.
+ darkness of the original image in that cell. Obviously, a large cell
+ size results in a heavy loss in resolution!
</para>
</sect3>
<sect3>
<title>Starting filter</title>
<para>
- You can find this filter through
+ This filter can be accessed through the menu:
<menuchoice>
<guimenu>Filters</guimenu>
<guisubmenu>Distorts</guisubmenu>
@@ -104,53 +98,93 @@
</figure>
<variablelist>
<varlistentry>
- <term>Preview</term>
+ <term>Presets, Input Type, Blending Options, Preview, Split view</term>
<listitem>
- <!-- changed 2010-05-17 ude: looks like just the opposite is true...
- Note that the preview displays the whole image, even if the final
- result will concern a selection.
- -->
- <para>
- All your setting changes will appear in the Preview without
- affecting the image until you click on <guilabel>OK</guilabel>.
- Note that the preview displays only a part of the whole image if
- the filter is applied to a selection. Don't keep
- <guilabel>Preview</guilabel> checked if your computer is too slow.
- </para>
+ <xi:include href="../about-common-features.xml"/>
</listitem>
</varlistentry>
<varlistentry>
- <term>Resolution</term>
+ <term>Channels</term>
<listitem>
<para>
- This group controls the cell size, either by setting the input and
- output resolutions, or directly.
+ This group controls the channels to use and the settings for each
+ channel.
</para>
<variablelist>
<varlistentry>
- <term>Input SPI</term>
+ <term>Color Model</term>
<listitem>
<para>
- Resolution of the original input image, in Samples Per Inch
- (SPI). This is automatically initialised to the input
- image's resolution.
+ Select which color inks to use:
+ <guilabel>White on Black</guilabel>,
+ <guilabel>Black on White</guilabel>,
+ <guilabel>RGB</guilabel>, or
+ <guilabel>CMYK</guilabel>.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>Output LPI</term>
+ <term>For each color ink or channel</term>
<listitem>
<para>
- Desired output resolution, in Lines Per Inch (LPI).
+ Settings that can be changed for each color ink or channel
+ are listed here.
</para>
+ <variablelist>
+ <varlistentry>
+ <term>Pattern</term>
+ <listitem>
+ <para>
+ Select the halftoning pattern to use. Choices are
+ <guilabel>Line</guilabel>, <guilabel>Circle</guilabel>,
+ <guilabel>Diamond,</guilabel>,
+ <guilabel>PSSquare (or Euclidian) dot</guilabel>,
+ <guilabel>Crossing Lines</guilabel>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Period</term>
+ <listitem>
+ <para>
+ The number of pixels across one repetition of a base
+ pattern at base resolution.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Angle</term>
+ <listitem>
+ <para>
+ The grid angle that should be used. This angle can be
+ adjusted with the slider, number entry, or using the
+ angle control by moving the arrow in the circle.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Black pullout</term>
+ <listitem>
+ <para>
+ This setting is only available when
+ <guilabel>CMYK</guilabel> was chosen as Color Model and
+ the selected channel is <guilabel>Black</guilabel>.
+ It regulates how much of common gray to pull out of
+ CMY.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
</listitem>
</varlistentry>
<varlistentry>
- <term>Cell size</term>
+ <term>Lock patterns, Lock periods, Lock angles</term>
<listitem>
<para>
- Resulting cell size, in pixels. Most often you will want to
- set this directly.
+ These three check boxes, if enabled, lock the settings
+ mentioned above to be the same for all channels. If
+ disabled, then these settings can be set individually for
+ each channel.
</para>
</listitem>
</varlistentry>
@@ -158,91 +192,52 @@
</listitem>
</varlistentry>
<varlistentry>
- <term>Screen</term>
+ <term>Quality</term>
+ <listitem>
+ <para>
+ <guilabel>Anti-alias oversampling factor</guilabel> This sets the
+ number of samples that are averaged for anti-aliasing the result.
+ </para>
+ <para>
+ Proper halftoning does not need anti-aliasing: the aim is to
+ reduce the color depth after all! However, since this
+ plug-in is mainly for special effects, the results are
+ displayed on screen instead of on a printer.
+ So it is often useful to apply a little anti-aliasing to
+ simulate ink smearing on paper. If you do want to print the
+ resulting image then set the antialiasing to 1 (i.e., off).
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effects</term>
<listitem>
<variablelist>
<varlistentry>
- <term>Separate To RGB, CMYK, Intensity</term>
- <listitem>
- <para>
- Select which colorspace you wish to operate in. In
- <emphasis>RGB</emphasis> mode, no colorspace conversion is
- performed. In <emphasis>CMYK</emphasis>, the image is first
- internally converted to CMYK, then each color channel is
- separately halftoned, before finally being recombined back
- to an RGB image. In <emphasis>Intensity</emphasis> mode,
- the image is internally converted to grayscale, halftoned,
- then the result used as the alpha channel for the input
- image. This is good for special effects, but requires a
- little experimentation to achieve best results. Hint: try
- CMYK if you don't know which to go for initially.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>Black pullout (%)</term>
+ <term>Turbulence</term>
<listitem>
<para>
- When doing RGB->CMYK conversion, how much K (black)
- should be used?
+ Color saturation dependent compression of period.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>Lock channels</term>
+ <term>Blocksize</term>
<listitem>
<para>
- Make channel modifications apply to all channels.
+ Number of periods per tile. This tiling avoids high
+ frequency anomalies that angle boost causes.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>Factory Defaults</term>
+ <term>Angle Boost</term>
<listitem>
<para>
- Restore the default settings which should give pleasing
- results.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>Angle</term>
- <listitem>
- <para>Cell grid angle for this channel.</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>Spot function</term>
- <listitem>
- <para>
- Spot function to be used for this channel (see preview in
- blue cell-boxes).
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>Antialiasing</term>
- <listitem>
- <para>
- Proper halftoning does not need antialiasing: the aim is to
- reduce the color depth after all! However, since this
- plugin is mainly for special effects, the results are
- displayed on screen rather than by a black/white printer.
- So it is often useful to apply a little anti-aliasing to
- simulate ink smearing on paper. If you do want to print the
- resulting image then set the antialiasing to 1 (i.e., off).
- </para>
- <variablelist>
- <varlistentry>
- <term>Oversample</term>
- <listitem>
- <para>
- Number of subpixels to sample to produce each output pixel.
- Set to 1 to disable this feature. Warning: large numbers
- here will lead to very long filter runtimes!
+ Multiplication factor for the desired rotation of the local
+ space for the texture. The way this is computed makes it weak
+ for desaturated colors and possibly stronger where there is
+ color.
</para>
</listitem>
</varlistentry>
@@ -252,19 +247,4 @@
</variablelist>
</sect3>
- <sect3>
- <title>Example</title>
- <figure>
- <title>Example for Newsprint</title>
- <mediaobject>
- <imageobject>
- <imagedata format="PNG"
- fileref="images/filters/examples/newsprint.png"/>
- </imageobject>
- <caption>
- <para>An example from plug-in author</para>
- </caption>
- </mediaobject>
- </figure>
- </sect3>
</sect2>
diff --git a/src/glossary/glossary.xml b/src/glossary/glossary.xml
index ca554f0c1..06ad8160b 100644
--- a/src/glossary/glossary.xml
+++ b/src/glossary/glossary.xml
@@ -688,7 +688,7 @@ https://gitlab.gnome.org/GNOME/gimp-help/tree/master/docs/xcf images folder-->
correct color is not available in the colormap.
</para>
<para>
- The <link linkend="plug-in-newsprint">Newsprint</link> filter
+ The <link linkend="gimp-filter-newsprint">Newsprint</link> filter
uses dithering as well. You can use the
<link linkend="plug-in-nlfilt">NL Filter</link> (Non Linear filter)
to remove unwanted dithering noise from your image.
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