World: r3wp
[AGG] to discus new Rebol/View with AGG
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Cyphre 18-May-2006 [803] | Another solution is to apply own translation function on the dialect block or generate the dialect block with translated coords from scratch. (this shouldn't be a rocket science and would work with text too) |
Volker 18-May-2006 [804x3] | Regarding text, maybe Graham is right and a graphics-only reverse would help? for diagrams. The current way is a bit complicated, until one gets the trick. |
means "apply own translation function on the dialect block". And now that little reversion-math, y: high - y . | |
now -> know | |
Pekr 18-May-2006 [807] | that would require one step above parser to draw dialect, no? |
Cyphre 19-May-2006 [808x2] | It's really easy: |
translate-draw: func [ height [integer!] blk [block!] /local dr p ][ parse blk [some ['draw set dr block! (parse dr [some [p: pair! (p/1: as-pair p/1/x height - p/1/y) | skip]]) | skip]] blk ] view layout [ origin 0 bx: box 400x400 black effect translate-draw 400 [ draw [ pen red line 50x50 350x50 pen blue line 50x50 50x350 pen yellow line 50x50 100x200 200x150 300x250 350x225 pen white text aliased 10x350 "Y axis" text aliased 320x40 "X axis" ] ] ] | |
Volker 19-May-2006 [810] | Looks like magic :) But should not be required to draw a line through some data? |
Graham 5-Jun-2006 [811x2] | rotate says it sets the clockwise rotation for draw commands. |
So, why does the text move across the page ? view/new layout [ b: box 400x400 black effect [ draw []] ] for i 0 90 5 [ b/effect: compose/deep [ draw [ rotate (i) text vectorial "This is a string of text 1" 300x75 ]] show b wait .2 ] | |
Henrik 5-Jun-2006 [813] | because the text rotates around 0x0 rather than around itself |
Graham 5-Jun-2006 [814] | should this be changed? |
Henrik 5-Jun-2006 [815x2] | which is what I figured you wanted to do. you need to make the text at 0x0, rotate it and then translate it to the position you want |
e.g. translate 100x100 rotate 30 text "something" | |
Graham 5-Jun-2006 [817] | or set up a straight line "spline" for the text ... |
Henrik 5-Jun-2006 [818] | possibly |
Graham 5-Jun-2006 [819] | Well, seems to me it should be changed. |
Henrik 5-Jun-2006 [820] | changed in AGG or in the code? |
Graham 5-Jun-2006 [821x5] | Text should rotate at the point where it is being drawn |
in AGG. | |
boxes don't rotate around 0x0 | |
why should text? | |
or do they ?? | |
Henrik 5-Jun-2006 [826x2] | well, if you did that, how would you rotate around another point? I won't argue for one solution or the other, but this approach seems natural enough to me. |
I think they do | |
Graham 5-Jun-2006 [828] | which approach? |
Henrik 5-Jun-2006 [829x3] | 1. first you draw 2. then you rotate 3. then you translate in classic REBOL order |
which means start at 3. :-) | |
speaking of which, it could be fun to see a LOGO like dialect for DRAW. fun for the kids. | |
Graham 5-Jun-2006 [832] | Gregg has one. |
Henrik 5-Jun-2006 [833] | that's good. I don't have to do it then. |
Graham 5-Jun-2006 [834] | do you have to create the kids first? |
Henrik 5-Jun-2006 [835] | got plenty of those around, not mine though. I don't know how interested they would be in it yet. I spent countless hours in COMAL80 when I was a kid drawing with the "turtle". |
Graham 5-Jun-2006 [836x2] | Comal80 - a Danish product? |
I remember I had a Comal80 interpreter for my C64. | |
Henrik 5-Jun-2006 [838x3] | I don't remember what it was. I think it was for several platforms but I used it for my C64. |
I think it was a great drawing tool. very straight forward approach to drawing. | |
then I got an Amiga and was exposed to the horror that was Amiga Basic. | |
Graham 5-Jun-2006 [841x3] | I've got my graphing utility written now in my postscript dialect |
just labelling the y-axis is a problem because of the way AGG does the rotate vs PostScript rotate command | |
and there's no way to save a graphic state in AGG. | |
Henrik 5-Jun-2006 [844] | ah, yeah that could be a problem |
Anton 5-Jun-2006 [845x4] | Graham, AGG rotation: that's just an effect of the way AGG does its transformations which apply to the whole image. The rotate command is just a shortcut method of specifying just the rotation angle of a transformation. |
transform (origin) (angle) (scale-x) (scale-y) (translate) | |
What you want to do is set the origin to the centre of your object, then change the angle and translate as you wish. | |
I agree that it is a bit uncomfortable at first. I was also expecting something simpler like in flash, but I suppose this way is more powerful. | |
Cyphre 5-Jun-2006 [849x3] | Anton is right. DRAW works on lower level than FACE so there is only one tranformation matrix per DRAW block (ie. it is applied on all rendered primitives). OTOH you have relatively wide range of commands how to control the transformation matrix or even use the mtrick stack to push/pop different trnasformation states to apply nested transfromations. |
(Note that due this lower-level approach the drawing is also faster.) | |
The transformation handling is more simmilar to OpenGL in that way. See some OGL docs to get the idea and you will see the benefits. | |
Geomol 4-Dec-2006 [852] | Is there a reason, why SPLINE doesn't draw anything with just two points? view layout [box effect [draw [pen black spline 10x10 90x90]]] |
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