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559 discussions

Announce: ctx2png
by Mariano Alvarez Fernandez 29 Apr '01

29 Apr '01

I want to announce first version of ctx2png. Ctx2Png is an addon to the GRX graphics library. It loads/saves a context from/to a PNG file. PNG is a lost-less compressed graphics format. It have lots of features, like the ability to handle an alpha channel. You can read more about the PNG format in http://www.libpng.org/pub/png/libpng.html The routines are not very efficient, but they work. Download: http://www.terra.es/personal/malfer/zipfiles/ctx2png.zip

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Error in ScanPoly
by Torsten Engelbrecht 27 Apr '01

27 Apr '01

I have found an error in the scanpoly.c (scan fill an arbitrary polygon) which is a part of the GRX graphics library. Under certain conditions a clipped polygon is not shown. This mistake appears with an example-triangle. It has the coordinates {{120, 0}, {120,90}, {0,60}} and is clipped by a rectangle {{50,50}, {270,150}} (with GrSetClipBox). The changed part of the fill algorithm can display this triangle. My changes are recognizable by the define NOERROR. The original source code can be found in directory shape. /** ** scanpoly.c ---- scan fill an arbitrary polygon ** ** Copyright (c) 1995 Csaba Biegl, 820 Stirrup Dr, Nashville, TN 37221 ** [e-mail: csaba(a)vuse.vanderbilt.edu] ** ** This file is part of the GRX graphics library. ** ** The GRX graphics library is free software; you can redistribute it ** and/or modify it under some conditions; see the "copying.grx" file ** for details. ** ** This library is distributed in the hope that it will be useful, ** but WITHOUT ANY WARRANTY; without even the implied warranty of ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. ** **/ #define NOERROR void _GrScanPolygon(int n, int pt[][2], GrColor color) { edge *edges, *ep; scan *scans, *sp, *points, *segments; int xmin, xmax, ymin, ymax; int ypos, nedges; int prevx; int prevy; int i; if ((n > 1) && (pt[0][0] == pt[n-1][0]) && (pt[0][1] == pt[n-1][1])) { n--; } if (n < 1) { return; } edges = (edge *)malloc(sizeof(edge) * (n + 2)); scans = (scan *)malloc(sizeof(scan) * (n + 8)); if (edges && scans) { /* * Build the edge table. Store only those edges which are in the * valid Y region. Clip them in Y if necessary. Store them with * the endpoints ordered by Y in the edge table. */ prevx = xmin = xmax = pt[0][0]; prevy = ymin = ymax = pt[0][1]; nedges = 0; ep = edges; while (--n >= 0) { if (pt[n][1] >= prevy) { ep->e.x = prevx; ep->e.y = prevy; ep->e.xlast = prevx = pt[n][0]; ep->e.ylast = prevy = pt[n][1]; } else { ep->e.xlast = prevx; ep->e.ylast = prevy; ep->e.x = prevx = pt[n][0]; ep->e.y = prevy = pt[n][1]; } #ifndef NOERROR if ((ep->e.y > GrHighY()) || (ep->e.ylast < GrLowY())) continue; clip_line_ymin(CURC, ep->e.x, ep->e.y, ep->e.xlast, ep->e.ylast); #endif if (ymin > ep->e.y) ymin = ep->e.y; if (ymax < ep->e.ylast) ymax = ep->e.ylast; if (xmin > ep->e.x) xmin = ep->e.x; if (xmax < ep->e.xlast) xmax = ep->e.xlast; setup_edge(&ep->e); ep->status = inactive; nedges++; ep++; } #ifndef NOERROR if ((nedges > 0) && (xmin <= GrHighX()) && (xmax >= GrLowX())) { if (xmin < GrLowX()) xmin = GrLowX(); if (ymin < GrLowY()) ymin = GrLowY(); if (xmax > GrHighX()) xmax = GrHighX(); if (ymax > GrHighY()) ymax = GrHighY(); #else if ((nedges > 0)) { #endif /* * Scan for every row between ymin and ymax. * Build a linked list of disjoint segments to fill. Rules: * (1) a horizontal edge in the row contributes a segment * (2) any other edge crossing the row contributes a point * (3) every segment between even and odd points is filled */ for (ypos = ymin; ypos <= ymax; ypos++) { #ifdef NOERROR if (ypos > GrHighY()) continue; if (ypos < GrLowY()) continue; #endif sp = scans; points = NULL; segments = NULL; for (n = nedges, ep = edges; --n >= 0; ep++) { switch (ep->status) { case inactive: if (ep->e.y != ypos) break; if (ep->e.dy == 0) { ep->status = passed; xmin = ep->e.x; xmax = ep->e.xlast; isort(xmin, xmax); add_scansegment(&segments, sp, xmin, xmax); sp++; break; } ep->status = active; case active: xmin = xmax = ep->e.x; if (ep->e.ylast == ypos) { ep->status = passed; xmax = ep->e.xlast; isort(xmin, xmax); add_scanpoint(&points, sp, xmin, xmax); sp++; } else if (ep->e.xmajor) { xstep_edge(&ep->e); xmax = ep->e.x - ep->e.xstep; isort(xmin, xmax); } else { ystep_edge(&ep->e); } add_scanpoint(&points, sp, xmin, xmax); sp++; break; default: break; } } while (points != NULL) { scan *nextpt = points->next; if (!nextpt) break; xmin = points->x1; xmax = nextpt->x2; points = nextpt->next; add_scansegment(&segments, nextpt, xmin, xmax); } while (segments != NULL) { xmin = segments->x1; xmax = segments->x2; segments = segments->next; clip_ordxrange_(CURC, xmin, xmax, continue, CLIP_EMPTY_MACRO_ARG); drawhline(xmin, ypos, xmax-xmin+1, color); } } } } if (edges) free(edges); if (scans) free(scans); } int left = 50; int top = 50; int right = 270; int bottom = 150; int n = 4; GrColor color = YELLOW; int pt[4][2]; int main() { GrSetClipBox(left, top, right, bottom); pt[0][0] = 120; pt[0][1] = 0; pt[1][0] = 120; pt[1][1] = 90; pt[2][0] = 0; pt[2][1] = 60; pt[3][0] = 120; pt[3][1] = 0; _GrScanPolygon(n, pt, color); }

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RE: How to draw rotated shape?
by Josu Onandia 27 Apr '01

27 Apr '01

In the case of a circle arc, it's easy: simply add or substract the rotation angle from the 'start' and 'end' params of the GrCircleArc function. Josu > -----Mensaje original----- > De: Hartmut Schirmer [SMTP:hartmut.schirmer@arcormail.de] > Enviado el: miércoles 25 de abril de 2001 16:51 > Para: tvt(a)usmtu.edu.ua > CC: grx(a)gnu.de > Asunto: Re: How to draw rotated shape? > > >How to draw a graphic shape (e.g. an ellipse or an arc) rotated by some > angle? > > no direct way. > Use GrGenerateEllipse() or GrGenerateEllipseArc() to create a polygon. > Then rotate the polygon point by point and finally draw it. > > Hartmut

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compiling under Cygwin?
by Zach Smith 26 Apr '01

26 Apr '01

Hi, I don't have a pointer to the 2.4 sources so I can't answer this question for myself: does GRX compile under Cygwin? Thanks ZS __________________________________________________ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/

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How to draw rotated shape?
by Theodore V. Tolstoy 25 Apr '01

25 Apr '01

Hi! How to draw a graphic shape (e.g. an ellipse or an arc) rotated by some angle? SY, Theodore

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[Fwd: Re: Compile GRX with Mingw]
by Mariano Alvarez Fernandez 24 Apr '01

24 Apr '01

-------- Original Message -------- Asunto: Re: Compile GRX with Mingw Fecha: Sat, 21 Apr 2001 00:23:45 +0200 De: Mariano Alvarez Fernandez <malfer(a)teleline.es> A: Waldemar Schultz <schultzma(a)mathematik.tu-muenchen.de> Referencias: <3AD0ECA1.41D6E0E0(a)teleline.es> <3AD159B8.8DCB55E2(a)ma.tum.de> <3AD1F992.66ECF8B2(a)teleline.es> <3AD2D051.848190B0(a)ma.tum.de> <3AD34CA2.40EB6285(a)teleline.es> <3AD4177E.7CB788BA(a)ma.tum.de> <3AD492B5.F7F1DF08(a)teleline.es> <3ADEDA70.EA6F4C32(a)ma.tum.de> Waldemar Schultz escribió: > when compiling MINGW/GRX/BGI programs I have noticed that if you use > setwritemode(XOR_PUT) once, setwritemode(COPY_PUT) does not switch back > to normal write mod but stays in xor-mode. > This effect does not occur in DJGPP/GRX/BGI environment. > Does anyone know a workaround ? No, sorry. It may be a bug (there are lots in the Win32 port at the moment). Can you provide a small test case? (I have never used the grx bgi interface).

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[Fwd: Re: Compile GRX with Mingw]
by Mariano Alvarez Fernandez 23 Apr '01

23 Apr '01

-------- Original Message -------- Asunto: Re: Compile GRX with Mingw Fecha: Sat, 21 Apr 2001 00:20:42 +0200 De: Mariano Alvarez Fernandez <malfer(a)teleline.es> A: Waldemar Schultz <schultzma(a)mathematik.tu-muenchen.de> Referencias: <3AD0ECA1.41D6E0E0(a)teleline.es> <3AD159B8.8DCB55E2(a)ma.tum.de> <3AD1F992.66ECF8B2(a)teleline.es> <3AD2D051.848190B0(a)ma.tum.de> <3AD34CA2.40EB6285(a)teleline.es> <3AD4177E.7CB788BA(a)ma.tum.de> <3AD492B5.F7F1DF08(a)teleline.es> <3ADEF8FE.9946EE8D(a)ma.tum.de> Waldemar Schultz escribió: > can anyone please tell me why getch() doesn't work in a console window ? > and what about thet kbhit(9 flushing in modetest.c ? > The win32 port provides GrKeyRead, GrKeyStat, kbhit, getkey and getch (the last three only for compatibility with old programs, without prototipe they in grx20.h). All functions use the GUI input. For read/write to console you need to read/write to stdin/stdout. See src/mouse/w32keys.c

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MINGW with GRX 2.4 from DJGPP/CONTRIB
by Waldemar Schultz 20 Apr '01

20 Apr '01

I am new to MINGW and I have to bring my DJGPP-C programs that use the GRX graphics contribution from DJGPP to Windows98 and Windows2000. I feel that MINGW could do the job, but I have severe problems with the mouse cursor, drawing in XOR-mode and keybord input. Does anyone out there use MINGW/GRX for MSWindows? If so any suggestions were highly appreciated. Thank you. -- Gruss Waldemar Schultz. Technische Universität München, Zentrum Mathematik M1, D 80290 München Tel: +49 (0)89 2892 8226 FAX: +49 (0)89 2892 8228

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Re: Compile GRX with Mingw
by Mariano Alvarez Fernandez 19 Apr '01

19 Apr '01

Waldemar Schultz escribió: > > Go to the src subdir and execute "make -f makefile.w32" > > O.K. > > > Go to the test subdir and execute "make -f makefile.w32" > > #66:W98 E:\DJGPP\CONTRIB\grx24\test>make -f makefile.w32 > gcc -o arctest.exe arctest.o ../lib/win32/libgrx20.a -lm -mwindows > arctest.o(.text+0x17):arctest.c: undefined reference to `mcount' > arctest.o(.text+0x549):arctest.c: undefined reference to `mcount' > arctest.o(.text+0x73a):arctest.c: undefined reference to `mcount' > arctest.o(.text+0xab5):arctest.c: undefined reference to `mcount' > ../lib/win32/libgrx20.a(fillell2.o)(.text+0x13):fillell2.c: undefined > reference > to `mcount' > ../lib/win32/libgrx20.a(w32keys.o)(.text+0x11):w32keys.c: more undefined > referen > ces to `mcount' follow > E:\MINGW\BIN\MAKE.EXE: *** [arctest.exe] Error 1 > It sounds like you have edited makedefs.gnu and defined the PROFILE macro, it is?

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MSVC support
by Schirmer, Hartmut 11 Apr '01

11 Apr '01

Hi, as promised some additional patches. Hartmut <<grx24.p2.bz2>>

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