Re: [Gimp-developer] Gsoc application for gegl porting

[Shlomi Fish <shlomif shlomifish org>]

Hi Jakub,

On Thu, 05 Apr 2012 01:59:48 +0200
noob7 <noob7 poczta onet pl> wrote:

> Hello,
> My name is Jakub Ozga. Iam 3rd year student on Gdansk University of Technology in Poland. I study computer science. I like to apply for Gegl porting project. I have already worked on 2 projects wich involved computer vision techniques supported by opencv library. Feel free to look at project site: http://sart2.eti.pg.gda.pl/en/index.php?language=en. I suggest to look at project and stuff sections.
>  
> Code Review and Algorithmic Description of GIMP Plug-ins
> 

Thanks for your enthusiasm, but I don't understand why you've written the text
(and code) below? Were they quoted from the project description?

Good luck in being accepted into Google Summer of Code, and I hope you will
stay involved in GIMP development afterwards.

Regards,

	Shlomi Fish

> Each Gimp plugin have functions:
> a)run
> Prepares parameters for mainfunction. Here dialog and mainfunction are called.
> b)query
> Creates array with type, name and description for each parameter. Then Installs procedure in procedure database,
> with given array.
> c)mainfunction
> Here everything is done.
> d)dialog
> Creates window to set preferences for mainfunction.
> e)optional preview
> Function that is optional depends on plugin. Shows preview image.
> #cubism
> 2. Get background color.
> 3. Fill image with background color.
> 4. Calculate number of tiles on Image.
> 5. Create array with length equals number of tiles. Put index value to each element.
> Randomize array by random picking 2 elemnts and swaping them.
> 6. Run loop with stop at value of tile number. In Loop use above array, randomize functions, tile size
> and saturation to calculate position for points, rotation angle and translation vector.
> 7. Create polygon within 4 calculated points. Rotate it by calculated angle. Translate polygon by vector.
> 8. Modify x and y values with CLAMP if needed.
> 9. Get color from modified(or not) x and y position from original Image.
> #fill_poly_color(run with x,y above and retrived color)
> 10. Pick first two points from Polygon. Calculate distance between them and get x, y vectors(normalized) for them.
> 11. Find maximum x,y and minimum x,y withing all points of Polygon. Get maximum width and height of Polygon.
> 12. Do scanline pattern for Polygon by height(rows).
> 13. Convert segments depending on min and max values of scanlines and cordinates of first Polygon point.
> 14. Calculate the color for each pixel of Polygon depending on scanlines and  other various calculations.
> #sinus
> 1. Create parameters:
> a) Set blending which depends on colorization.
> b) Create 3 objects, each contains random values like int, double and angle.
> c) Do tiling to those 3 objects. Then move them to parameters.
> d) Get 2 colors which were perviously defined. Modify those colors and do color2 - color1 with substracting rgba values.
> e) Multiply color2 and set color2 to parameters.
> 2. Get starting point and ending point of rectangle which represent the user selection.
> 3. Depending on bits per pixel retrived from original image run computing block for each destination region.
> 4. Assign color to each pixel for region using parameters, sinus and blending power.
> #decompose
> 1. Get the type of image(RGB,HUE...). Types are defined at the top of the source.
> 2. Check if source image contains atleast 3 bits per pixel and if source image have alpha channel.
> 3. Define number of new gray images. This number equals specified number which is defined for each image type. Note that
> this number cannot exceed maximum number of layers generated by extraction( #define MAX_EXTRACT_IMAGES)
> 5. Creating images in loop. Image creation includes creating new image with type(BaseType = GIMP_GRAY), filename, resolution and layer.
> 6. For each soruce pixel region extract channel information and modify channels.
> 7. Update each Layer(Emit signal) and add alpha channel to each Layer.
> 8. return number of new images created.
> #gaussian-blur
> 1. Run iir or rle blur functions which depends on configuration and depends also on the blur radius (bug).
> Each method uses 2 steps to achieve results: Divide process on 2 passes: vertical and horizontal.
> @IIR
> 2. Calculate vertical standard deviation.
> 3. Find Gaussian constants using standard deviation.
> 4. If image has alfa(ex. rgb, gray) then transform alpha channel.
> 5. Set up 2 initial arrays for color.
> 6. Do the gaussian calculations using source image, above arrays and constants.
> 7. If image has alfa then convert alfa channel from premultiplied to separate one.
> 8. Do steps 2-7 with diffrent orientation.
> @RLE
> 2. Calculate vertical standard deviation.
> 3. Fill gauss curve using standard deviation.
> 4. Do the same steps as iire except step 6 which here its diffrent:
> -If a lot of pixels are repeated then run fastest algorithm for this case
> else run slower one but easier to understand.
>  
> Sample implementation
> diff --git a/examples/hi.c b/examples/hi.c
> index e69de29..e26d04a 100644
> --- a/examples/hi.c
> +++ b/examples/hi.c
> @@ -0,0 +1,37 @@
> +#include <gegl.h>
> +#include <glib/gprintf.h>
> +
> +gint main (gint argc, gchar **argv)
> +{
> +   g_thread_init (NULL);
> +   gegl_init (&argc, &argv); 
> +  
> +   if(argc!=2){
> +       g_print("Please provide filename with png format!\n");
> +       return -1;
> +   }
> +   GeglNode *gegl = gegl_node_new ();
> +   GeglNode *over       = gegl_node_new_child (gegl, "operation", "gegl:over", NULL);
> +   GeglNode *load       = gegl_node_new_child (gegl, "operation", "gegl:png-load", "path", argv[1],   NULL);
> +   GeglNode *text       = gegl_node_new_child (gegl, "operation", "gegl:text", "size", 10.0, "color", gegl_color_new ("rgb(1.0,1.0,1.0)"), NULL);
> +   GeglNode *display    = gegl_node_create_child (gegl, "gegl:display");
> +   GeglRectangle rect   = gegl_node_get_bounding_box(load);
> +   GeglBuffer* buffer   = gegl_buffer_new(&rect,babl_format ("RGBA float"));   
> + 
> +   gegl_buffer_save(buffer, "newBuffer", &rect);
> +   gegl_node_link_many (load, over, display, NULL);
> +   gegl_node_connect_to (text, "output",  over, "aux");
> +
> +   int i=0;
> +   for(;i<100;i++){
> +       gchar string[512];
> +       g_sprintf (string, "%d",i);
> +       gegl_node_set (text, "string", string, NULL);
> +       gegl_node_process (display);
> +   }
> +
> +   g_object_unref (gegl);
> +   gegl_exit ();
> +
> +   return 0;
> +}



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Shlomi Fish       http://www.shlomifish.org/
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