To learn a bit about what sodipodi does let's make a simple example consisting of a city skyline at twilight.
When you first run sodipodi you are confronted by a rather daunting toolbox of little icons. These tools are broken in to groups by the class of operations they perform. For example, everything to do with files, such as saving and creating a new page are grouped together in the 'File' section.
Obviously we need a new document if we are to draw anything. Click the new file button (the top left icon in the file section). Notice that if you just leave your cursor over the icon a tooltip appears describing the tool.
Sodipodi differs from The GIMP in that it remembers pictures as a set of simple elements, such as lines, circles and stars. The picture you see is thus a representation of the actual image constructed everytime you move the window or zoom in our out.
One of the big advantages of this approach is that the resulting image is sharp on screen, but also when you print it on a printer the curves come out smooth and the lines meet in beautifully sharp points. We'll look at printing later.
Another advantage of sodipodi's approach is that we can change any aspect of the image at any time. If, after showing the client, we find that the background is too dark we can edit its colour or position without needing to start from scratch. It's a bit like layers in The GIMP, but we have access to the commands that made each layer.
Ok, lets get down to business! Let's start by making a simple boxy skyline. First, draw a horizon line across the middle of the page to base the work on. To do this select the pencil tool from the draw section:
We may not need this line when we've finished, but I find it helped me get into the drawing part. Just click on the left side of the page, then, holding down the control key, click on the right edge.
Now, click out a random skyline. To do this I switched to the Pen tool. It is the second element down the menu that pops up when you click and hold on the Pencil tool. (XXX: If you like your skyline to be realistic, then you can use the control key to enforce axis parallel lines.) If you, like me, want a more cartoon feel to the design, then use sloping lines.
To finish a path with the pen tool you can either click on the little green square where you started the path, or you can double click.
A single skyline looks fairly unconvincing - let's add some depth by creating a few more lines of towers!
Obviously a line only version of this isn't too convincing... To make the images solid we choose the select tool (the arrow) and select the set of towers we want to change:
Then, click on the fill settings icon (the tipping bucket of paint in the object section). Up should pop a dialog with four icons under the row of tabs. The 'X' icon is currently highlighted (this means no fill at all). Click on the plain blue square. Immediately the row of towers gets painted black. I don't want my towers to be solid black, instead I've changed them to be shades of indigo, to set the mood for a twilight scene.
If you, like me, find it hard to get the colours right in RGB (red green blue) mode, change the colour space by clicking on the little 'Mode:' menu.
This skyline is a nice starting point, but it lacks any kind of focus. Let's put a big tower in to give it some bite. Again I've used the pen tool to build a nice forboding tower. However, to add to the nightmare quality I switched to the Node tool (second icon in Draw) and pulled the sides in a little.
The node tool is a little hard to use. When you select an object with the node tool lots of little diamonds appear on the corners of your object. These are called 'Nodes' in sodipodi parlance (other programs call them things like 'vertices', 'control points' or 'knots'). Each diamond is changing point on the curve or line. If you click on a diamond a little circle appears inside the diamond. This is a curve control point (XXX: no visible name for these?)
To give my picture a bit of home, I added a drawing of the arts centre from my home city, Melbourne. It made it by drawing a triangle, bending the sides in and adding a few extra lines to represent the steel lattice it is made from:
Because all of the lines represent a single element, namely the arts centre, I've grouped them together. To do this I selected all the individual elements and chose "Group selected objects" from the selection section in the tool palette. Now these elements are selected together when you click on any of them.
Another nice tool is the star tool. Following the theme of Melbourne, I've decided to put in a southern cross star constellation. The star tool is in the same menu as the rectangle tool in the Draw section.
If you bring up the tool attributes with the star tool you have the option of how many points, and how point those points are. Let's say your forgot this before you drew the star. One way to change any attribute of a sodipodi image is to use the XML editor.
The XML editor dialog is an alternative way to look at the structure of your drawing. Remember that sodipodi builds pages from simple elements? Well you can see exactly how those elements are arranged in the XML editor.
Select one of your stars and bring up the XML editor dialog by right clicking on the window. A menu pops up. Choose Dialogs -> XML Editor.
I've clicked on one of my stars. When you so, you get a list of attributes that that element has. Click on the side attribute. Notice that the number of sides appears in the editable field down the bottom. Change this to another number, say 7. To save you change back to the window, click the button with the up arrow. Instantly the star in the drawing will change to match.
I think the city looks a little odd at the moment with its white background. Let's create a proper sky. I'm using a rectangle, as sodipodi doesn't appear to allow you to give a document a background colour.
Ok, I don't like it. The sky dominates the picture. Rather than filling it with a solid colour, we'll instead colour it with a gradient. Gradients are blends from one colour to another. There are two sorts provided by sodipodi - linear gradients, that run from one colour to another colour in a certain direction; and radial gradients, which expand from a single point.
To build this image I've duplicated the sky a few times, building up the fading sky. Sodipodi's gradients currently can only move from one colour to another colour - eventually they will be able to move through a selection of colours like in The GIMP. I've tried to fake this behaviour by putting a few layers of linear gradients on top of each other to get the desired sky, but as you can see, it wasn't entirely successful. :-(
(XXX: The muddy colours indicate a poor mixing algorithm for the gradient.)
I also put a bright radial gradient to represent the sun's lightening of the sky. Again, when sodipodi has more complex rules for the gradient editor we could add a lens flare through the buildings or sparks off the windows.
In case you've been wondering how I put my intermediate results on the web, sodipodi has an 'export' item in the file menu (remember, right click on the image, just like The GIMP). 'export' renders your drawing to a png (XXX:other formats?). Eventually web browsers will handle SVG natively (recent versions of mozilla in fact do, although on my machine the results aren't pretty). Then we can just refer to our images like we refer to pngs, jpgs and gifs!
Let's make this into a title page for something. How about "Nightmare on flinders street"? I'd like the title to be blood red and some kind of emphasis on the word nightmare.
To add text to an image we use the 'Text' tool in the Draw section. Click somewhere off your drawing and type "Nightmare" (or something else, if you want something a little less scarey ;). The text is so small it's unreadable! You could zoom in and make sure it's right, but I just assumed mine was correct. Then, while the carat is still in the text, click the 'Text and font settings' icon in the Object section. I chose 'Becker' font, and a size of 72 pixels.
Then move the text into position on your drawing and use the 'fill settings' (paint bucket) to set the colour of the text.
For more emphasis you could set the outline colour of the text by clicking on the 'Stroke settings' icon, next to 'Fill settings'. I just set my stroke colour to black.
To me the text just looks like it was typed in over the top. Let's play a bit with the outline of the text and make it more appealing. Sodipodi can convert some text into the set of curves required to describe the font. To do so, we click on the 'convert to curves' button in the Object section.
Nothing happened! Try selecting the text with the Node tool... Now each letter is made up of its component curves. We can move them around and edit them just like we did for the dark tower.
Finally, the subtext of the the title - "on flinders street". I want this to swish across the image. First, type in the text. I used a font called 'brush-stroke'.
Make it red, as before. Now, to make it swish across the picture I need to rotate the image. To do this I click on the text twice with the Select tool. Notice the arrows change from radial to angular? You can move the centre of rotation around by dragging the little cross hairs inside the selection. Then, while holding down the shift key, grab a corner arrow and drag.
Versions of sodipodi more recent than version 0.31 have support for the new fontconfig system. This has many nice attributes, such as antialiased fonts everywhere, but the nicest thing is that to add a font to your system you only have to follow 3 steps:
~/.fonts directory, e.g. download Tengwar
Cursive, unzip it and move the Tengwarc.ttf file into
~/.fonts/fc-cache - this tells fontconfig to look in all
the usual places (including your .fonts directory) and
remember all the fonts availableOk, now you want some nice elvish? Make a new document, draw a gold rectangle and maybe add some glints of light to it:
Ok, now to add the text. I don't know tengwar, so I'm just going to steal the example off that tengwar cursive site, namely:
AE5,Ex26Yw1E\x{00BE}^z\x{00B3}= AE5,ExxwP%1Ej^
AE5,Ex37zE1E\x{00BE}^z\x{00B3}= X#w6Ykt^AT`Bz7qpT1Ej^
Click on the text tool, and type some random characters (You can't paste in new text in my version - you have to update an existing text field). Click on text properties icon (with the ABC) and change your random characters to the ones given above.
So where is the tengwar? scroll down the font list and you should (fingers crossed!) see Tengwar Cursive listed! Chose that, press apply, and tada! Instant ring to rule them all!
I fiddled a bit with the stroke colour (which controls the outline on the text). That's it for now :)
(XXX: how to print results)
This document is released under the Gnu Documentation License.
