####################################################
Date: Sat, 30 Jul 2005 22:07:29 +0100 From: sam ende <sam@sende.co.uk> Subject: [Fractint] xfractint To: fractint@mailman.xmission.com Message-ID: <200507302207.29657.sam@sende.co.uk> Content-Type: text/plain; charset="us-ascii"
hallo, i'm new to the list and wondering how to improve the resolution/increase the picture size of images to avoid the jaggedness in images such as this: http://www.sende.co.uk/fract038.gif i'm using xfractint on debian sarge. thanks for any tips or links to tutorials.
sammi
Sammi, 'Jaggies' are caused by what is called spatial aliasing. When viewing information on raster-based computer displays (both CRTs and LCDs) it is a result of sampling and viewing information at evenly spaced intervals. I do two things to combat spatial aliasing in my images. 1) I'm not familiar with the X-Fractint version of Fractint, but I assume that most of the same basic keystrokes are the same. To change the number of pixels in an image hit the <del> key (in the DOS version) and choose a higher resolution from the list of resolutions. The jaggies will decrease -- the higher the resolution of the final image, the smaller the jaggies. Many of these resolution choices supplied with Fractint are tuned to support particular graphics cards and will likely not work on your graphics card. Keep trying choices until you find the ones that work on your graphics card. The first ones to try have 'VESA' in their name. They are compatible with many graphics cards. There may be some resolutions that your card does not support. There may be some resolutions that your card supports that are not included in the default list of resolution choices. You can add to the list of resolution choices by adding lines to the Fractint control file: FRACTINT.CFG Knowing what values to put into the control registers of your graphics card usually takes detailed information about the card. However, the use I make of this file does not need this information. See below for how to modify the file and why. 2) To decrease the jaggies of a particular fractal at a given image size I calculate the image at an increased resolution (say two or four times the final intended resolution) and then use an image manipulation program to average the values of multiple adjacent pixels together. This averaging process both reduces the resolution to the final intended resolution and reduces the jaggies at the same time. You must be *certain* that the graphics manipulation program does combine the adjacent pixels and does not just resample the image -- resampling effectively throws away the extra pixels you have calculated. I have found that increasing the resolution by a factor of four in X and Y and then averaging four adjacent pixels in both X and Y gives results pleasing to me on images that originally had objectionable jaggies when calculated at a resolution of 1024 x 768. How objectionable jaggies are is both a function of the data in a particular image and of the mindset of the person viewing the image. I only use the method described above for images that I am willing to devote the 16 times more calculation time to. Calculating images at resolutions of 2048 x 1536 or 4096 x 3072 means that you need to use what is called Fractint's Disk/RAM 'Video' feature since it is likely that your graphics card will not display images at these resolutions. There are some Disk/RAM 'Video' resolutions already in the FRACTINT.CFG file I mentioned earlier, but not the resolutions listed above. However, it is easy to add your own Disk/RAM 'Video' lines in the configuration file. Simply find a Disk/RAM 'Video' resolution that works on your machine (they all should, unless X-Fractint has some special problem with Disk/RAM 'Video') and create another line that looks the same as the one that works -- with the X and Y resolutions changed. Here is an original line and two lines that I added to my DOS FRACTINT.CFG File ("clr" stands for "# of colors"): ; FRACTINT.CFG File ;key |name of adapter/mode|AX|BX|CX| DX |mode| x | y | clr | comments ;=========================================================================== ====== . . . ,Disk/RAM 'Video' , 3, 0, 0, 0, 11,1024, 768,256,For Background Fractals ,Disk/RAM 'Video' , 3, 0, 0, 0, 11,2048,1536,256,/For Bkgnd 2*(1024 x 768) ,Disk/RAM 'Video' , 3, 0, 0, 0, 11,4096,3072,256,/For Bkgnd 4*(1024 x 768) Spacing/tabs appear not to be critical in this file in DOS Fractint. In a previous posting to these email lists I noted that in modern machines during the use of "Disk/RAM 'Video'", RAM is used to hold the pixel values during the calculation -- your disk is never used. But don't forget to save your image after calculating it using Disk/RAM 'Video' mode! ====================================================== Please let me know if adding resolution lines works as easily in X-Fractint as it does in the DOS version of Fractint! ====================================================== And whether you like the results you get using the averaging method. -------------------------------------------------------
thanks for any tips or links to tutorials. Here you go: http://spanky.triumf.ca/ and http://spanky.triumf.ca/www/fractint/preslar.html http://members.aol.com/billatny/fractopi.htm
A number of the links given on the above pages have aged out. You may be able to locate the original pages in the "Wayback Machine" internet archive: http://www.archive.org/web/web.php I tested the following links and they appear to be working: Fractint Tutorial (Bill Rossi) [Note that new features have been added to later versions of Fractint over time.] http://members.aol.com/billatny/Fractint_Tutorial.htm WELCOME to the Fractint Development Team WWW pages http://www.fractint.org/ An Introduction to the Fractint Formula Parser http://spanky.triumf.ca/www/fractint/frm-tut/frm-tutor.html Anti-Aliasing Explained (Damien M. Jones) http://www.fractalus.com/info/antialias.htm Fractal Information Page (Damien M. Jones) http://www.fractalus.com/info/ PNG vs. JPEG discussed (Damien M. Jones) http://www.fractalus.com/info/png-jpeg.htm ------------------------------------------------------- I have put a copy of my own "Basic Fractint 'Cheat Sheet'" below. - Hal Lane ######################### # hallane@earthlink.net # ######################### ------------------------------------------------------ Basic Fractint 'Cheat Sheet' Note: You need to be viewing a fractal or partially created fractal to type in many of the commands given below. The keystrokes don't need to be capital letters. <Esc> - go to the Main Menu page - most major commands are listed there. <Esc><Esc>Y - exits Fractint. <F1> - get help. Different help screens appear depending on what you are doing. <Tab> - view info about current (possibly incomplete) image. ------------ T - choose Type of fractal to create. S - Save image. A partial image can be saved. When reloaded *most* fractal types will continue being created. R - Reload existing image. X - set the name of the file to save the fractal in, if you do not want to use the auto-naming feature of Fractint -- which creates file names of the form: FRACTnnn.GIF You may remember that Fractint by default automatically changes the name of each new fractal you create so you never overwrite an existing file. The File Name is 8 letters maximum with a 3 letter file extension since Fractint is a DOS program. The X (Basic Options) page also allows you to change the maximum iterations used to calculate each pixel among other items. ------------ <PgUp> - shows the zoom box. Decreases the size of the 'zoom box' <PgDn> - increases the size of the 'zoom box'. Increase to the full size of the image and the 'zoom box' is removed. --------------- while the 'zoom box' is displayed <Enter> - 'zoom in'. This triggers the calculation and display of the fractal contained within the 'zoom box' at the current screen size. This can be done to a partially calculated image. <Ctrl><Enter> - 'zoom out'. A 'reverse zoom'. This triggers the calculation and display of the current full image size being shrunk down to the size of the 'zoom box'. Thus an additional area outside the current image will be seen in the calculated image. <arrow_keys> - move the 'zoom box' <Ctrl><arrow_keys> - move the 'zoom box' five times as fast. If you have mouse support in DOS the mouse will move the 'zoom box'. You don't have to hold the left mouse button to move the 'zoom box'. A double click will trigger the calculation and display of the fractal contained within the 'zoom box'. Holding the right mouse button while moving the mouse to the left or right rotates the 'zoom box'. ------------ C - enter Color cycling mode. (Type <F1> for help on Color Cycling.)
, <, period, comma - These four keys cycle colors when held down. You can load different color maps using this feature. E<Enter> - enter palette Editing mode. (Type <F1> for help on Palette Editing.) , <, period, comma - These four keys smoothly cycle colors when held down. You can load multiple color maps using this feature and switch between them using one keystroke.
V - set View window options When creating fractals that take a quite a while to calculate I use the View options to quickly calculate a reduced size image to see if it has promise. An Auto Window Size Reduction Factor of 4 will draw the fractal 1/4 the size in X and Y -- and it will be created 16 times faster than a full screen image. VY<Enter> is the keystroke sequence I memorized that turns image size reduction on. VN<Enter> returns to calculating full screen images You can also set a lower resolution screen size, say 640 x 480 -- or smaller, by using the <Del> key to speed up looking at a fractal you might create at a higher resolution later, but you will see the individual horizontal lines on the screen which I don't like. The View Window Size Reduction method allows you to set a size reduction factor of higher than 4 to get a quick look at extremely slow fractals -- or a quicker look at slow fractals. <Del> - set the screen resolution in pixels (Set Video Mode page). Note that some video modes do not work on certain video cards. The 'Disk Video' modes can be used to create fractals without their being viewed during creation. Note that these fractals must still be saved when completed. I use this to calculate slow fractals at full screen size after I have zoomed and located them in the reduced-size viewing mode. Type <Del> and scroll down until you see the video modes with: Disk/RAM 'Video' in their name. <PgUp> and <PgDn> as well as the arrow keys scroll through the list of video modes. ------------- <Alt><Enter> switch between a full screen view of Fractint and Fractint in a window. This is a Windows command, not a Fractint command. You may or may not be able to do this successfully. Under Windows 98 I cannot interact successfully with Fractint while it is in a window, and I can only change to viewing Fractint in a window while Fractint is showing a text page, but I can use my machine to look at email etc. while it is windowed. Other versions of Windows may differ in their behavior. ---------------------------------------------------------------------------- ---------- #################################################### -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.338 / Virus Database: 267.9.9/62 - Release Date: 8/2/05