#27 Where is the One-Pixel-Size-Point?

[Stefan Menzel]

Hi PlPlot Programmers,

I really like your PLPLot, but I cant find the function to do draw a point with the size of maximal one pixel of the Display.

PlPoin with code=1 draws only 4 Pixels with one pixel-hole.

I want to draw a Logistic map, isn't this possible with PLPlot?

Thanks for Your efforts
Stefan Menzel

[Stefan Menzel]

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Like in PGPlot with code -1 :

PGPT -- draw several graph markers

void cpgpt(int n, const float *xpts, const float *ypts, int symbol);

SUBROUTINE PGPT (N, XPTS, YPTS, SYMBOL)
INTEGER N
REAL XPTS(*), YPTS(*)
INTEGER SYMBOL

Primitive routine to draw Graph Markers (polymarker). The markers
are drawn using the current values of attributes color-index,
line-width, and character-height (character-font applies if the symbol
number is >31). If the point to be marked lies outside the window,
no marker is drawn. The "pen position" is changed to
(XPTS(N),YPTS(N)) in world coordinates (if N > 0).

Arguments:
N (input) : number of points to mark.
XPTS (input) : world x-coordinates of the points.
YPTS (input) : world y-coordinates of the points.
SYMBOL (input) : code number of the symbol to be drawn at each
point:
-1, -2 : a single dot (diameter = current
line width).
-3..-31 : a regular polygon with ABS(SYMBOL)
edges (style set by current fill style).
0..31 : standard marker symbols.
32..127 : ASCII characters (in current font).
e.g. to use letter F as a marker, let
SYMBOL = ICHAR('F').
> 127 : a Hershey symbol number.

Note: the dimension of arrays X and Y must be greater than or equal
to N. If N is 1, X and Y may be scalars (constants or variables). If
N is less than 1, nothing is drawn.

[Werner Smekal]

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Hi Stefan,

how this the symbol with the code #1 is drawn to the screen or to a file depends on the driver used and which font this driver uses. If you look at the example 6 http://plplot.sourceforge.net/examples/demo06.php I think that this is a point. This is the pngcairo device I think. Depending on what you need (screen plots, png plots) you could try the different devices (xwin, xcairo, wxwidgets) and also try to turn freetype library on and off with the -drvopt text=0|1 option. Alternativ you could try to draw a line from (x,y) to (x,y) I think you will get a point then for most drivers.

HTH,
Werner

[Stefan Menzel]

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Hi Werner,

thanks for fast reply, which helped locating the problem:

I use WinXP (please continue reading... :-)), VC-2008EE and the WinGCC-Driver.
I tried png (GD-Driver) and code=-1 and voila there's my One-Pixel-Point.
I installed freetype and tried WinGCC with "-drvopt text" option but also no success, it draws nothing for code=-1.
I tried hard to install wxwidget but this is impossible with the latest software versions (I will submit a bug, in the bug section).
So I think the WinGCC-Driver has a bug.
As additional information, I have problems with correct visualisation in examples No. 23,24, even with activated Freetype and not using WinGCC-Driver.

[Alan W. Irwin]

Closed (too old).