Commit 46044403 authored by Niklas Mattisson's avatar Niklas Mattisson

Modified ChangeLog. Add the first port of the GIMPLite Quickies tutorial.

Modified ChangeLog.
Add the first port of the GIMPLite Quickies tutorial.
parent b9c8a8ce
2002-12-06 scizzo <scizzo@gimp.org>
* tutorials/Lite_Quickies/: Add the first port of the GIMPLite
Quickies tutorial.
2002-12-06 carol <carol@gimp.org>
* tutorials/Anti-Alias_Treshhold/, tutorials/Anti-Alias_Threshhold:
......
<!--#include virtual="/includes/header_pretitle.inc" -->
<title>GIMP - jpeg race</title>
<!--#include virtual="/includes/header_posttitle.inc" -->
<div id="main">
<div class="heading">jpeg race</div>
<table>
<tr><td>
<img src="sunspot_swedish_label2.jpg" width="401" height="291" alt="original"/><br />
<p>original</p>
</td><td>
<img src="flip-sample-h.png" width="401" height="291" alt="horizontal"/><br />
<p>horizontal flip</p>
</td></tr>
<tr><td>
<img src="flip-sample-v.png" width="401" height="291" alt="vertical"/><br />
<p>vertical flip</p>
</td><td>
<img src="flip-sample-b.png" width="401" height="291" alt="both"/><br />
<p>horizontal and vertical flips</p>
</td></tr></table>
</div>
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<span id="footerleft">
Tutorial &copy; 2002 <a href="mailto:carol@gimp.org">Carol Spears (carol)</a>
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<!--#include virtual="/includes/header_pretitle.inc" -->
<title>GIMP - GIMPLite Quickies</title>
<!--#include virtual="/includes/header_posttitle.inc" -->
<div id="main">
<div class="heading">GIMPLite Quickies</div>
<div class="subtitle">Intention</div>
<p>
So, you have The GIMP installed on your computer, you need to make a quick change to an image for some project, but don't want to learn about
computer graphics right now in order to get the image changed. Totally understandable. The GIMP is a powerful image manipulator with many options and tools.
However, it is quick and somewhat intuitive (after a time) for the small jobs as well. Hopefully, these quickies will help you with your quick problem and help
you to stay friends with The GIMP and ready for its more complex tools and methods later, when you have the time and inspiration.
</p>
<p>
A couple of words about the images used here. The came from <a href="http://antwrp.gsfc.nasa.gov/apod/astropix.html">APOD</a>,
Astronomy Picture Ofthe Day. The screenshots were taken on my desktop which is sporting this <a href="http://antwrp.gsfc.nasa.gov/apod/ap020328.html">APOD</a> image.
</p>
<p>
All you should need to know to start here is how to find your image and open it. <span class="filter">File-&gt;Open</span>.
</p>
<div class="subtitle">Change the Size of an Image (Scale)</div>
<p class="images">
<a href="scale-menu.png"><img src="scale-menu-t.png" alt=""/></a>
<a href="scale-dialog.png"><img src="scale-dialog-t.png" alt=""/></a>
</p>
<p>
Problem: you have a huge image and you want to put it nicely for viewing on a web page. The GIMP is a quick solution.
Our example image is this beauty <a href="m51_hallas_big.jpg" alt=""/>m51_hallas_big.jpg</a> from <a href="http://antwrp.gsfc.nasa.gov/apod/ap020710.html">APOD</a>.
</p>
<p>
The first thing that you might notice is that The GIMP opens the image at a logical size for viewing.
So, if your image is really big (like the sample image) it will display it zoomed out until it fits nicely.
You can tell if The GIMP has done this by the percentage number in the title bar.
(you can click on the little screenshot to see the full view of the screenshot) Just because it looks right in this "View" doesn't mean anything.
</p>
<p>
The other thing to look at in the titlebar is the mode. If it says RGB in the title bar, you are fine.
If it says Indexed or grayscale there, you should read the Change the Mode Quickie.
</p>
<p>
Image entry in the menu and the sub menu from the screenshot should revel itself. Click on "Scale Image...".
When ever you click an option from the menu that has ... behind it, expect another dialog. This time, you should get the "Scale Image Dialog".
</p>
<p>
If you have a desired width, put it in the dialog at the top where it says "New Width". If you don't have such a number in mind,
you can steal the width of The GIMP's default image size, which is 256 pixels. This is demonstrated in this <a href="scale-dialog1.png">screenshot</a>.
You can see the image that this scale dialog produced <a href="m51_hallas_256.jpg">here</a>.
</p>
<p>
Perhaps you want your image to look more like a 4x6 inch photo on most image rendering web browsers.
Simply switch the units to "inches" and put 4 inches in the height box (opting for smaller than 4x6 rather than bigger).
You can see this dialog <a href="scale-dialog2.png">here</a>. The image this dialog produced <a href="m51_hallas_6x4.jpg">here</a>.
</p>
<p>
Let The GIMP choose the other dimension length for you. Meaning, it will take more image knowledge to change both width
and height and have it look correct. So only change one and let The GIMP change the rest. To change the other length see the crop quickie.
</p>
<div class="subtitle">Make jpegs Smaller</div>
<p class="images">
<a href="jpegsave-menu.png"><img src="jpegsave-menu-t.png" alt=""/></a>
<a href="jpegsave-dialog-de-t.png"><img src="jpegsave-dialog-de.png" alt=""/></a>
</p>
<p>
You can make your jpegs smaller without changing the pixel width of the image. Actually you can change the weight of the image a lot.
I used an(other) image from <a href="http://antwrp.gsfc.nasa.gov/apod/ap020215.html">APOD</a>.
The <a href="lordofrings_hst_big.jpg">original image</a> is huge (3000 pixels wide) so I also made a
<a href="lordofrings_hst_med.jpg">smaller (pixel width)</a> image available.
To prepare this image for the web, you should first reduce the image to a better width and height for web viewing as described in the scale quickie.
Right click on the properly scaled image and follow the menus <span class="filter">&lt;Image&gt;File-&gt;Save As....</span>
The <a href="save-dialog.png">Save Dialog</a> will pop up.
</p>
<p>
I generally type the filename I want into the text box, but the Extension drop menu can tell you the available file formats
(depending on the libraries you have installed and the conditions of the image you are trying to save). If The GIMP complains right now,
or if "JPEG" is grayed out in the Extensions menu you should just cancel out of everything and step through the Change the Mode Quickie.
</p>
<p>
In the JPEG Save Dialog, you can opt for The GIMP defaults which reduce the size quite a bit, without hurting the visual quality in a way that I can detect.
This would be the safest and quickest thing to do.
</p>
<p>
If you would like to make it smaller still, make sure that the "Preview" toggle is on and then watch the image area and change the
compression level by moving the "Quality" slider down. You can see the quality of the image changing, especially towards the leftmost end of the slider.
<a href="jpegsave-sample.png">Here</a> is a screenshot of me doing this very thing. As you can see, very small is also very bad.
I have a screenshot of me setting the Quality slider to a more acceptable level <a href="jpegsave-sample1.png">here</a>.
</p>
<p>
I have not been showing the actual jpegs I created so that we could end this quickie with a race. Clicking <a href="jpegrace.html">this page</a>
should "race" these jpegs to a web page (the first time you see an image in most browsers, you are also waiting for it to write to the cache,
so the first time is the worst). With my cable modem, I was unable to see a difference in the load time,
but the difference in what you actually see is fairly interesting.
</p>
<div class="subtitle">Crop An Image</div>
<p class="images">
<img src="crop-button.png" alt=""/>
<a href="crop-menu.png"><img src="crop-menu-t.png" alt=""/></a>
<a href="crop-dialog.png"><img src="crop-dialog-t.png" alt=""/></a>
</p>
<p>
Many reasons to need to crop an image. Making rectangles square, or making squares into rectangles. Cutting alot of useless background
to bring out the subject better. etc. To get to the crop tool, you can either push the button on the toolbox or right click on the image
and follow the menu <span class="filter">&lt;Image&gt;Tools-&gt;Transform Tools-&gt;Crop &amp; Resize</span>.
This will change the cursor and allow you to click and drag a rectangular shape. Once again,
I have chosen one of the huge and beautiful <a href="http://antwrp.gsfc.nasa.gov/apod/ap021108.html">APOD</a> images,
<a href="ngc6369_heritage_big.jpg">ngc6369 heritage</a>.
</p>
<p>
I always click on the approximate upper left corner and drag to the lower <a href="crop-drag.png">right corner</a>. You don't need to worry about being accurate
on this first swipe with the crop tool, since a little dialog will pop up and you can make a better choice for your new borders there..
</p>
<p>
Here is the little "Crop &amp; Resize Information Dialog". This screenshot is showing the information about the borders we defined in our click and drag.
We will have to change all of the numbers. If you would like to make this rectangular image square, you should find the width and height
from the Get Image Information Quickie. Use the smallest of the two lengths to determine the size of the square. In my 300 x 226 pixel image,
the best I can get is a 226 x 226 pixel square, and I will need to make sure the Y origin is 0. At that point, I use the image and the squares
to get the best part of the image for the area. The upper right and lower left crop squares will move the border preview box.
The other two will change the dimensions, so be careful. I have a <a href="crop-dialog1.png">screenshot</a> of this,
right after I fixed the width and height and the Y origin, but before the final positoning. The arrows show the move points.
</p>
<p>
I decided that the image looked the best with the <a href="crop-dialog2.png">X Origin at 39</a>. The final image appears <a href="ngc6369_heritage_sq.jpg">here</a>.
</p>
<div class="subtitle">Find Info About Your Image</div>
<p class="images">
<a href="info-menu.png"><img src="info-menu-t.png" alt=""/></a>
<a href="info-dialog.png"><img src="info-dialog-t.png" alt=""/></a>
</p>
<p>
This window will tell you the pixel lengths. Right click on the image and follow <span class="filter">&lt;Image&gt;View-&gt;Info Window...</span> Here is a screenshot of a
<a href="info-calculator.png">calculator</a> which also gives lots of good information. I got another image from
<a href="http://antwrp.gsfc.nasa.gov/apod/ap001113.html">APOD</a> It is pretty big. You can see in the dialog above, it is 2241 x 1548 pixels.
</p>
<p>
If you are just making a square out of a rectangle, like in the Crop An Image Quickie, you need only to open the dialog and find
the lesser length and use that as described. Since this is very little information, and definately not enough to fill the space
between the menu thumbnail and the dialog screenshot in my layout, I thought I would run through some calculator exercises
that might help you to meet your image needs.
</p>
<p>
It is nice to have images appear on a browser window as a photo would. Photos online appear to be 4x6 inches when scaled to
288x432 pixels (72 dpi for many monitors). There is a <a href="info-scale.png">problem</a>, however, if you try to scale this image.
The ratio of width to length of the original does not match the ratio of the photo. So, to make the scaled image
the correct size crop 10 pixels from the height. For the sample image, it was best to <a href="info-crop-4x6.png">crop</a> 10 pixels off from the top.
The final <a href="quintet_hst_6x4.jpg">image</a> should "appear" as a 6x4 inch photo on most monitors.
</p>
<p>
You can change the Resolution of your image as well, using the same methods as we used in the Scale, although, in my somewhat limited use,
the issue is more about how many pixels. Let's say you want to get this image printed at the photo lab. 300 pixels for every inch is necessary.
This original image will print easily as a 7 x 5 photo. 2241px/300ppi = 7.47in. Get out your calculator for the short side. 1548/300 = _.
</p>
<p>
There is another brutal fact you should come to terms with if you are new to graphics and computers. Just because it looks good on the screen
(the <a href="quintet_hst_6x4.jpg">image</a> from before) doesn't mean that it will print that nicely.
I tried to emulate how this image would appear printed at 300dpi <a href="quintet_hst_emul.jpg">here</a>. Sorry. There are some options,
for instance my friend printed images and then scanned them back in. Terrible business!
</p>
<div class="subtitle">Change the Mode</div>
<p class="images">
<a href="mode-menu.png"><img src="mode-menu-t.png" alt=""/></a>
<img src="mode-dialog.png" alt=""/>
</p>
<p>
When you are using The GIMP and some of your options are "<a href="mode-sample.png">grayed</a>" or it complained when you tried to save it and you didn't like
the results of agreeing to "<a href="mode-export.png">Export</a>" it, quite often it is an image that is the wrong Mode. I can see the image mode in my window decoration.
Change the mode via right click on the image and then follow the menus through <span class="filter">&lt;Image&gt;Image-&gt;Mode-&gt;</span>List of Available Modes.
Using another <a href="http://antwrp.gsfc.nasa.gov/apod/ap950622.html">APOD</a> image, lets check out modes ...
</p>
<p>
Usually, when your options are grayed out in the menu, you need for the image to be <a href="mode-menu2.png">RGB, not Indexed</a>. It is the difference in how the
color information is understood. Indexed is 256 or less colors, is small but lacks information and is difficult to manipulate.
RGB is millions of colors, easier to manipulate yet quite big to remember all these millions of colors.
Check this first when determining why you cannot select something from a menu or get that "<a href="mode-export.png">Export</a>"
</p>
<p>
The next most common issue you might be having with grayed out plug-ins and other options is <a href="mode-alpha.png">Alpha</a>.
Don't worry about Alpha beyond these two facts. 1) you cannot have transparent areas on your image without it.
2) you cannot save as a jpeg with it. Right click on the image and follow the menus <span class="filter">&lt;Image&gt;Layers-&gt;Add Alpha Channel</span>.
If it is <a href="mode-alphano.png">grayed out</a>, you have this alpha channel already and your image is ready to have transparency.
The way to remove the alpha channel is not so obvious. Right click on the image, <span class="filter">Layers-&gt;Flatten Image</span>
<a href="mode-flatten-menu.png">removes the alpha channel</a>, makes the menu entry gray.
Some plug-ins want the Alpha Channel, some don't, so be prepared to try it both ways.
</p>
<p>
<b>Case of grayed out JPEG option:</b><br />
<a href="mode-jpegno.png"><span class="filter">&lt;Image&gt;File-&gt;Save As...</span>[Extension: JPEG]</a> is not an option.
First, <a href="mode-flatten-menu.png"><span class="filter">&lt;Image&gt;Layers-&gt;Flatten Image</span></a>.
Then <a href="mode-menu.png"><span class="filter">Image-&gt;Mode-&gt;RGB</span></a>
</p>
<p>
<b>Case of not being able to erase:</b><br />
<a href="mode-alpha.png"><span class="filter">&lt;Image&gt;Layers-&gt;Add Alpha Channel</span></a>, should do the trick.
A Sample of both types on one image can be seen <a href="mode-sample2.png">here</a>.
</p>
<p>
<b>Case of grayed out GIF option:</b><br />
<a href="mode-gifno.png"><span class="filter">&lt;Image&gt;File-&gt;Save As...</span>[Extension: GIF]</a> is not an option.
<a href="mode-menu.png"><span class="filter">&lt;Image&lt;Image-&gt;Mode-&gt;Indexed....</span></a>
Best to just hit "Okay" in the <a href="mode-index.png">dialog</a> that pops up.
</p>
<div class="subtitle">Flip An Image</div>
<p class="images">
<img src="flip-button.png" alt=""/>
<a href="flip-menu.png"><img src="flip-menu-t.png" alt=""/></a>
<img src="flip-dialog.png" alt=""/>
</p>
<p>
When you need the person in the photo looking in the other direction, or you need to top of the image to be the bottom.
Mirroring the image (sort of). Right click on the image and follow the menus <span class="filter">&lt;Image&gt;Tools-&gt;Transform Tools-&gt;Flip</span>,
or use the button on the toolbox.
</p>
<p>
Using another <a href="http://antwrp.gsfc.nasa.gov/apod/ap021114.html">APOD</a> image I demonstrated all
of the flips on <a href="sunspot_swedish_label2.jpg">this</a> image. You might get bored before it is over ....
</p>
<p>
The tool used as is (the default) will do <a href="flip-sample-h.png">this</a> to an image.
</p>
<p>
If you double click on the button, up will pop the means to flip images vertically as well. I did just that on <a href="flip-sample-v.png">this</a> image.
</p>
<p>
For a really big finish, I flipped <a href="flip-sample-b.png">this</a> image both ways. At least it is such a cool image for all of this silliness.
</p>
<p>
The flips are all displayed on one page for you, <a href="flips.html">here</a>. One might ask themselves, useful? or filler for a pre-established format?
</p>
<div class="subtitle">Rotate An Image</div>
<p class="images">
<a href="rotate-menu.png"><img src="rotate-menu-t.png" alt=""/></a>
</p>
<p>
Let's say you turned your brand new digital camera to get a vertical shot, now some of your images are on their sides.
Right click on the image, and follow the menus <span class="filter">&lt;Image&gt;Image-&gt;Transforms-&gt;Rotate-&gt;90 degrees</span> (or 270 depending on the orientation).
Using an <a href="http://antwrp.gsfc.nasa.gov/apod/ap000228.html">APOD</a> image. I rotated it once to demonstrate. <a href="sombrero_vlt-270.jpg">270 degrees</a>.
</p>
</div>
<!--#include virtual="/includes/tutnavbar.inc" -->
<div>
<span id="footerleft">
Tutorial &copy; 2002 <a href="mailto:carol@gimp.org">Carol Spears (carol)</a>
</span>
<span id="footerright">
<a href="mailto:webmaster@gimp.org">webmaster@gimp.org</a>
</span>
</div>
</body>
</html>
<!--#include virtual="/includes/header_pretitle.inc" -->
<title>GIMP - jpeg race</title>
<!--#include virtual="/includes/header_posttitle.inc" -->
<div id="main">
<div class="heading">jpeg race</div>
<table>
<tr><td>
<img src="cmprssed.jpg" width="350" height="175" alt="cmprssed.jpg"><br>
<p>Quality .06</p>
</td><td>
<img src="compressed.jpg" width="350" height="175" alt="compressed.jpg"><br>
<p>Quality .38</p>
</td></tr>
<tr><td>
<img src="default.jpg" width="350" height="175" alt="default.jpg"><br>
<p>Quality .75</p>
</td><td>
<img src="uncompressed.jpg" width="350" height="175" alt="uncompressed.jpg"><br>
<p>Quality 1.00</p>
</td></tr></table>
</div>
<!--#include virtual="/includes/tutnavbar.inc" -->
<div>
<span id="footerleft">
Tutorial &copy; 2002 <a href="mailto:carol@gimp.org">Carol Spears (carol)</a>
</span>
<span id="footerright">
<a href="mailto:webmaster@gimp.org">webmaster@gimp.org</a>
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