[gimp-help-2] Updates and corrections for selections (part 1).
- From: Roman Joost <romanofski src gnome org>
- To: svn-commits-list gnome org
- Cc:
- Subject: [gimp-help-2] Updates and corrections for selections (part 1).
- Date: Mon, 26 Oct 2009 07:57:47 +0000 (UTC)
commit 4347cc3f916caad6b77962593c9adc6e2dbc6ff8
Author: Andrew Pitonyak <andrew pitonyak org>
Date: Thu Oct 22 16:25:13 2009 -0400
Updates and corrections for selections (part 1).
src/concepts/selection.xml | 127 ++++++++++++++++++++++---------------------
src/using/selections.xml | 47 ++++++++++------
src/using/web.xml | 99 ++++++++++++++++++----------------
3 files changed, 146 insertions(+), 127 deletions(-)
---
diff --git a/src/concepts/selection.xml b/src/concepts/selection.xml
index ca38127..3ca30fc 100644
--- a/src/concepts/selection.xml
+++ b/src/concepts/selection.xml
@@ -28,7 +28,7 @@
<emphasis>selecting</emphasis>
that part. Each image has a <emphasis>selection</emphasis>
associated with it. Most, but not all, <acronym>GIMP</acronym> operations
- act only on the selected portions of the image.
+ act only on the selected portions of the image.
</para>
<figure>
<title>How would you isolate the tree?</title>
@@ -40,15 +40,15 @@
</figure>
<para>
There are many, many situations where creating just the right selection is
- the key to getting the result you want, and often it is not very easy to
+ the key to getting the result you want, and often it is not easy to
do. For example, in the above image, suppose I want to cut the tree out
- from its background, and paste it into a different image. In order to do
+ from its background, and paste it into a different image. To do
this, I need to create a selection that contains the tree and nothing but
- the tree. It is difficult because the tree has a very complex shape, and
+ the tree. It is difficult because the tree has a complex shape, and
in several spots is hard to distinguish from the objects behind it.
</para>
<figure>
- <title>Selection shown as usual with dashed line</title>
+ <title>Selection shown as usual with dashed line.</title>
<mediaobject>
<imageobject>
<imagedata fileref="images/using/select-outline.png" format="PNG"/>
@@ -58,10 +58,11 @@
<para>
Now here is a very important point, and it is crucial to understand this.
Ordinarily when you create a selection, you see it as a dashed line
- enclosing a portion of the image. The idea you could get from this is that
+ enclosing a portion of the image. The common, not entirely accurate,
+ idea you could get from this, is that
the selection is a sort of container, with the selected parts of the image
- inside, and the unselected parts outside. This concept of the selection is
- okay for many purposes, but it is not really correct.
+ inside, and the unselected parts outside. Although this concept of
+ selection is okay for many purposes, it is not entirely correct.
</para>
<para>
Actually the selection is implemented as a <emphasis>channel</emphasis>.
@@ -78,11 +79,12 @@
What, then, is the dashed line that appears when you create a selection?
</para>
<para>
- It is a <emphasis>contour line</emphasis>, dividing areas that are more
+ The dashed line is a <emphasis>contour line</emphasis>, dividing areas
+ that are more
than half selected from areas that are less than half selected.
</para>
<figure>
- <title>Same selection in QuickMask mode</title>
+ <title>Same selection in QuickMask mode.</title>
<mediaobject>
<imageobject>
<imagedata format="PNG"
@@ -91,8 +93,8 @@
</mediaobject>
</figure>
<para>
- You should always bear in mind, when looking at the dashed line that
- represents the selection, that it only tells you part of the story. If you
+ While looking at the dashed line that represents the selection, always
+ remember that the line tells only part of the story. If you
want to see the selection in complete detail, the easiest way is to click
the QuickMask button in the lower left corner of the image window. This
causes the selection to be shown as a translucent overlay atop the image.
@@ -100,15 +102,14 @@
completely selected an area is, the less red it appears.
</para>
<para>
- QuickMask mode, and its uses, are described in detail below. Meanwhile, if
- you are following this discussion by trying things out in
- <acronym>GIMP</acronym>, you should
- know that many operations work differently in QuickMask mode, so go ahead
- and toggle it off again for now (by clicking the QuickMask button once
- more).
+ Many operations work differently in QuickMask mode, as mentioned in the
+ <link linkend="gimp-image-window-qmask-overview"
+ >QuickMask overview</link>.
+ Use the QuickMask button in the lower left corner of the image window to
+ toggle QuickMask mode on and off.
</para>
<figure>
- <title>Same selection in QuickMask mode after feathering</title>
+ <title>Same selection in QuickMask mode after feathering.</title>
<mediaobject>
<imageobject>
<imagedata format="PNG"
@@ -124,37 +125,38 @@
Rectangle Select tool, create sharp selections. Pixels inside the dashed
line are fully selected, and pixels outside completely unselected. You
can verify this by toggling QuickMask: you see a clear rectangle with
- sharp edges, surrounded by uniform red. In the Tool Options, however, is
- a checkbox called <quote>Feather edges</quote>. If you enable this, the
- tool will instead create graduated selections. The feather radius, which
+ sharp edges, surrounded by uniform red.
+ Use the <quote>Feather edges</quote> checkbox in the Tool Options to
+ toggle between graduated selections and sharp selections.
+ The feather radius, which
you can adjust, determines the distance over which the transition
occurs.
</para>
<para>
- If you are following along, try this out with the Rectangle Select tool,
- and then toggle QuickMask. You will now see that the clear rectangle has
+ If you are following along, try this with the Rectangle Select tool,
+ and then toggle QuickMask. You will see that the clear rectangle has
a fuzzy edge.
</para>
<para>
- Feathering is particularly useful when you are cutting and pasting, in
- helping the pasted object to blend smoothly and unobtrusively with its
+ Feathering is particularly useful when you are cutting and pasting, so
+ that the pasted object blends smoothly and unobtrusively with its
surroundings.
</para>
<para>
- Actually, it is possible to feather a selection at any time, even if it
- was originally created as a sharp selection. You can do this from the
- image menu, by choosing
+ It is possible to feather a selection at any time, even if it
+ was originally created as a sharp selection. Use
<menuchoice>
<guimenu>Select</guimenu>
<guimenuitem>Feather</guimenuitem>
- </menuchoice>.
- This brings up a dialog that allows you to set the feather radius. You
- can do the opposite--sharpen a graduated selection into an
- all-or-nothing selection--by choosing
+ </menuchoice> from the image menu to open the Feather Selection dialog.
+ Set the feather radius and click OK.
+ This brings up a dialog that allows you to set the feather radius. Use
<menuchoice>
<guimenu>Select</guimenu>
<guimenuitem>Sharpen</guimenuitem>
</menuchoice>.
+ do the opposite—sharpen a graduated selection into an
+ all-or-nothing selection—.
</para>
<note>
<para>
@@ -170,31 +172,32 @@
<para>
You can set layer opacity, but you cannot do that directly for a
selection. It is quite useful to make the image of a glass
- transparent. You can achieve this by using these methods:
+ transparent. Use the following methods to set the layer opacity:
</para>
<itemizedlist>
<listitem>
<para>
- For simple selections, use the Eraser tool with the wanted opacity.
+ For simple selections, use the Eraser tool with the desired opacity.
</para>
</listitem>
<listitem>
<para>
- For complex selections: use the command
+ For complex selections: use
<menuchoice>
<guimenu>Selection</guimenu>
<guimenuitem>Floating</guimenuitem>
</menuchoice>
- to create a floating selection. This creates a new layer called
- <quote>Floating Selection</quote>.
+ to create a floating selection. This creates a new layer with
+ the selection called <quote>Floating Selection</quote>.
- Set the opacity slider in the Layer Dialog to get the wanted opacity.
+ Set the opacity slider in the Layer Dialog to the desired opacity.
Then anchor the selection: outside the selection, the mouse pointer
- comes with an anchor icon. When you click, the floating selection
+ includes an anchor. When you click while the mouse pointer includes
+ the anchor, the floating selection
disappears from the Layer Dialog and the selection is at the right
place and partially transparent (anchoring works this way only if a
- selection tool is activated : you can also use the command in the
- context menu that you get by right clicking on the selected layer
+ selection tool is activated : you can also use the Anchor Layer
+ command in the context menu by right clicking on the selected layer
in the layer dialog).
</para>
<para>
@@ -206,46 +209,46 @@
<keycombo action="press">
<keycap>Ctrl</keycap>
<keycap>V</keycap>
- </keycombo> to paste it, creating so a floating selection, adapt
- the opacity then make Layer/New Layer that pastes the floating
- selection into the new layer. You can also create a shortcut for
- the New Layer command to use keys only.
+ </keycombo> to paste the clipboard as a floating selection, and
+ <menuchoice>
+ <guimenu>Layer</guimenu>
+ <guimenuitem>New Layer</guimenuitem>
+ </menuchoice> to turn the selection into a new layer.
+ You can adjust the opacity before, or after creating the new layer.
</para>
</listitem>
<listitem>
<para>
- Another way:
+ Another way: use
<menuchoice>
<guimenu>Layer</guimenu>
<guisubmenu>Mask</guisubmenu>
- <guimenuitem>Layer mask</guimenuitem>
+ <guimenuitem>Add Layer Mask</guimenuitem>
</menuchoice>
to add a layer mask to the layer with the
selection, initializing it with the selection. Then use a brush with
- the wanted opacity to paint the selection with black, i-e paint it
+ the desired opacity to paint the selection with black, i-e paint it
with transparency. Then Layer/Mask/Apply Layer Mask. See
<xref linkend="gimp-layer-mask"/>.
</para>
</listitem>
<listitem>
<para>
- If you want to <emphasis>make transparent the solid
- background of an image</emphasis>, add an Alpha channel and select
- the background by using the Magic Wand. Then, with the Color Picker
- tool, select the background color which becomes the foreground
- color in Toolbox. Use Fill tool with this color on the selection,
- in the <quote>Color Erase</quote> mode. This method erases pixels
- which have this color; other pixels are partially erased and their
- color is changed.
+ To <emphasis>make the solid background of an image
+ transparent</emphasis>, add an Alpha channel, and use the Magic
+ Wand to select the background. Then, use the Color Picker
+ tool to select the background color, which becomes the foreground
+ color in Toolbox. Use the Bucket Fill tool with the selected color.
+ Set the Bucket Fill mode to <quote>Color Erase</quote>, which erases
+ pixels with the selected color; other pixels are partially erased
+ and their color is changed.
</para>
<para>
- The simplest method is the
+ The simplest method is to use
<menuchoice>
<guimenu>Edit</guimenu>
- <guimenuitem>Erase</guimenuitem>
- </menuchoice>
- command, which gives complete transparency to a selection and
- doesn't allow to enjoy the Opacity setting of the Fill tool.
+ <guimenuitem>Clear</guimenuitem>
+ </menuchoice>, which gives complete transparency to a selection.
</para>
</listitem>
</itemizedlist>
diff --git a/src/using/selections.xml b/src/using/selections.xml
index 0b3b2a6..81d4e5a 100644
--- a/src/using/selections.xml
+++ b/src/using/selections.xml
@@ -30,10 +30,10 @@
</indexterm>
<para>
- Rectangular and elliptical selections show up in two modes. Default
- mode is with handles. If you click the selection or press the
- <keycap>Enter</keycap> key, you only get the dotted outline
- (marching ants) and no handles. The other selection tools have
+ Rectangular and elliptical selections have two modes. The default
+ mode has handles on the selection. If you click the selection or
+ press the <keycap>Enter</keycap> key,the handles disappear leaving
+ only the dotted outline (marching ants). The other selection tools have
different behaviour.
</para>
@@ -41,14 +41,15 @@
<title>Moving rectangular and elliptical selections</title>
<para>
If you click-and drag a selection with handles, you move the
- selection outline and you don't move the contents of rectangular or
+ selection outline, and you don't move the contents of rectangular or
elliptic selections.
</para>
<para>
- You can also use the
- <link linkend="gimp-tool-move">Move </link> tool to move the selection
- outline.
+ Select the <link linkend="gimp-tool-move">Move </link> tool and set
+ the options to move the selection; the tool supports moving the
+ selection, path, or layer.
</para>
+
<figure>
<title>Moving selection outline</title>
<mediaobject>
@@ -58,12 +59,16 @@
</mediaobject>
</figure>
<para>
- You can also use <keycap>Alt</keycap> (or
- <keycombo><keycap>Ctrl</keycap><keycap>Alt</keycap></keycombo> on some
- systems) and the arrow keys to move the selection outline one by one
- pixel. With
- <keycombo><keycap>Shift</keycap><keycap>Alt</keycap></keycombo> and
- arrow keys you can move it by 25 pixels steps.
+ Most systems support moving the selection using the arrow keys.
+ The precise behavior is system dependent. If the arrow keys do not
+ cause the selection to move, try hovering the mouse cursor over the
+ selection first. Press and hold the <keycap>Alt</keycap> (or
+ <keycombo><keycap>Ctrl</keycap><keycap>Alt</keycap></keycombo>,
+ <keycombo><keycap>Shift</keycap><keycap>Alt</keycap></keycombo>, or
+ <keycap>Alt</keycap>). One combination may move the selection by one
+ pixel, and another by 25 pixels each step. Hover the mouse cursor over
+ a side or corner handle, and the arrow keys and combinations can
+ change the size of the selection.
</para>
<para>
If you click-and-drag the selection without handles, you create a new
@@ -76,6 +81,11 @@
<keycombo><keycap>Ctrl</keycap><keycap>Alt</keycap></keycombo>
keys and click-and-drag the selection. This makes the original
place empty. A floating selection is created.
+ The required key commands may differ on your system, look in the
+ status bar to see if another combination is specified; for
+ example,
+ <keycombo><keycap>Shift</keycap><keycap>Ctrl</keycap>
+ <keycap>Alt</keycap></keycombo>.
</para>
<figure>
<title>
@@ -112,10 +122,11 @@
</itemizedlist>
<note>
<para>
- On some systems, it's preferable to push first the
- <keycap>Alt</keycap> key, otherwise if you push first the
- <keycap>Shift</keycap> or <keycap>Ctrl</keycap> keys, GIMP will
- fall over add/subtract to the current selection mode and after
+ On some systems, you must push <keycap>Alt</keycap> before
+ <keycap>Shift</keycap> or <keycap>Ctrl</keycap>. On these
+ systems, pressing <keycap>Shift</keycap> or <keycap>Ctrl</keycap>
+ first, causes GIMP to enter a mode that adds or subtract from the
+ current selection — after
that, the <keycap>Alt</keycap> key is ineffective!
</para>
</note>
diff --git a/src/using/web.xml b/src/using/web.xml
index 4101433..72ca14c 100644
--- a/src/using/web.xml
+++ b/src/using/web.xml
@@ -19,11 +19,11 @@
</indexterm>
<para>
- One of the most common purposes <acronym>GIMP</acronym> is used for
- is to prepare images for adding them to a web site. This means that
+ One of the most common uses for <acronym>GIMP</acronym>,
+ is to prepare images for web sites. This means that
images should look as nice as possible while keeping the file
- size as small as possible. This little step-by-step guide will tell
- you how to achieve a smaller file size with minimal degradation of
+ size as small as possible. This step-by-step guide demonstrates
+ how to create small files with minimal loss of
image quality.
</para>
@@ -31,14 +31,12 @@
<title>Images with an Optimal Size/Quality Ratio</title>
<para>
An optimal image for the web depends upon the image type and the file
- format you have to use. If you want to put a photograph with a lot of
- colors online, you have to use
- <link linkend="file-jpeg-save">JPEG</link>
- as your primary file format. If your image contains fewer colors, that
- is, if it is not a photograph, but is more a drawing you created (such
- as a button or a screenshot), you would be better off using
+ format. Use <link linkend="file-jpeg-save">JPEG</link> for
+ Photographs because they usually have many colors and great detail.
+ An image with fewer colors, such as a button, icon, or screenshot, is
+ better suited to the
<link linkend="file-png-load">PNG</link>
- format. We will guide you through the process of doing this.
+ format.
</para>
<procedure>
<step>
@@ -64,39 +62,41 @@
<link linkend="gimp-image-flatten">flattening the image</link>.
</para>
<para>
- If you open a photograph, you probably won't have to remove the
- alpha channel, because a photograph doesn't usually have one, so the
- file is already opened in RGB mode.
+ A photograph rarely has an alpha channel, so the image will open
+ in RGB mode rather than RGBA mode; and you won't have to remove
+ the alpha channel.
</para>
<note>
<para>
If the image has a soft transition into the transparent areas, you
- cannot remove the alpha channel, since the information which would
- be used for fading out will not be saved in the file. If you would
- like to save an image with transparent areas which do not have a
+ should not remove the alpha channel, since the information
+ used for the transition is not be saved in the file.
+ To save an image with transparent areas that do not have a
soft transition, (similar to
<link linkend="file-gif-save">GIF</link>),
- you can remove the alpha channel.
+ remove the alpha channel.
</para>
</note>
</step>
<step>
<para>
- After you have flattened the image, you are able to
+ After you have flattened the image,
<link linkend="gimp-file-save">save the image</link>
- in <link linkend="file-png-save-defaults">PNG format</link>
+ in the <link linkend="file-png-save-defaults">PNG format</link>
for your web site.
</para>
</step>
</procedure>
<note>
<para>
- You can save your image in PNG format with the default settings, but
- using maximum compression. Doing this will have no negative affects on
- the quality of the picture, as it would have with
- <link linkend="file-jpeg-save">JPEG</link>
- format. If your image is a photograph with lots of colors, you would
- be better off saving it as jpeg. The main thing is to find the best
+ You can save your image in the PNG format with the default settings.
+ Always using maximum compression when creating the image.
+ Maximum compression has no affect on image quality or the time
+ required to display the image, but it does take longer to save.
+ A <link linkend="file-jpeg-save">JPEG</link> image, however,
+ loses quality as the compression is increased.
+ If your image is a photograph with lots of colors, you should
+ use jpeg. The main thing is to find the best
tradeoff between quality and compression. You can find more
information about this topic in <xref linkend="file-jpeg-save"/>.
</para>
@@ -108,11 +108,12 @@
<para>
If you want to reduce the size of your image a bit more, you could
convert your image to Indexed mode. That means that all of the colors
- will be reduced to only 256 values. Converting images with smooth color
- transitions or gradients to indexed mode will often give poor results,
- because it will turn the smooth gradients into a series of bands. This
- method is also not recommended for photographs because it will make the
- image look coarse and grainy.
+ will be reduced to only 256 values. Do not convert images with
+ smooth color transitions or gradients to indexed mode, because
+ the original smooth gradients are typically converted into a
+ series of bands. Indexed mode is not recommended for photographs
+ because after the conversion, they typically look coarse and
+ grainy.
</para>
<figure>
<title>The indexed image</title>
@@ -124,7 +125,7 @@
<caption>
<para>
An indexed image can look a bit grainy. The left image is Wilber
- in its original size, the right one is zoomed in by 300 percent.
+ in its original size, the right image is zoomed in by 300 percent.
</para>
</caption>
</mediaobject>
@@ -133,13 +134,13 @@
<step>
<para>
Use the command described in <xref linkend="gimp-image-mode"/>
- to convert your RGB image to indexed mode.
+ to convert an RGB image to indexed mode.
</para>
</step>
<step>
<para>
- After you have converted the image to indexed mode, you are once
- again able to <link linkend="gimp-file-save">save</link> your
+ After you convert an image to indexed mode, you are once
+ again able to <link linkend="gimp-file-save">save</link> the
image in <link linkend="file-png-save-defaults">PNG
format</link>.
</para>
@@ -157,18 +158,18 @@
There are two different approaches used by graphic file formats
for supporting transparent image areas: simple binary transparency
and alpha transparency. Simple binary transparency is supported
- in <link linkend="file-gif-save">GIF</link> format. Here, one color
+ in the <link linkend="file-gif-save">GIF</link> format; one color
from the indexed color palette is marked as the transparent color.
- Alpha transparency is supported in
- <link linkend="file-png-save-defaults">PNG</link> format. Here, the
+ Alpha transparency is supported in the
+ <link linkend="file-png-save-defaults">PNG</link> format; the
transparency information is stored in a separate channel, the
<link linkend="glossary-alpha">Alpha channel</link>.
</para>
<note>
<para>
- There is usually no need to save images in GIF format any more,
- because PNG supports all the features of GIF and offers additional
- features (e.g., alpha transparency). Nevertheless, this format is
+ The GIF format is rarely used
+ because PNG supports all the features of GIF with additional
+ features (e.g., alpha transparency). Nevertheless, GIF is
still used for animations.
</para>
</note>
@@ -199,16 +200,20 @@
verify that an entry for <quote>Alpha</quote> exists, besides
Red, Green and Blue. If this is not the case,
<link linkend="gimp-layer-alpha-add">add a new alpha channel</link>
- from the layers menu.
+ from the layers menu;
+ <menuchoice><guimenu>Layer</guimenu><guimenu>Transparency</guimenu>
+ <guimenuitem>Add Alpha Channel</guimenuitem></menuchoice>.
</para>
</step>
<step>
<para>
- You can now remove the background layer to get a completely
- transparent background, or create a gradient from color to
- transparency. You are only limited by your imagination. To
- demonstrate the capabilities of alpha transparency, we'll make a
- soft glow in the background around our Wilber.
+ The original XCF file contains background layers that you can
+ remove. GIMP supports standard filters that support creating
+ gradients; look under <menuchoice><guimenu>Filters</guimenu>
+ <guimenu>Light and Shadow</guimenu></menuchoice>.
+ You are only limited by your imagination. To
+ demonstrate the capabilities of alpha transparency, a
+ soft glow in the background around Wilber is shown.
</para>
</step>
<step>
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