Classname: XwEzDrawWidgetClass
 
 

Header files: WEzdraw.h public header

WEzdrawP.h private header

Description:

Example of a standard drawing:

Resources:

Detailed Description of special Resources:

Callbacks:

XwNdestroyCallback, XmNexposeCallback, XmresizeCallback, XmNinputCallback. Depending on type of callback, the items within the callbackstructure will have slightly different meaning. The most important callback, I think, will be the Input-Callback, as it returns the scaled position of the cursor.

Callback Structure:

typedef struct {
int reason;
XEvent *event; int fd;
float x_value;
float y_value;
float x_max;
float y_max;

}XwEzdrawCallbackStruct;

Expose: x_value/x_max abscissa minimum/maximum scaled

y_value/y_max ordinate minimum/maximum..scaled

Resize: x_value/x_max abscissa minimum/maximum scaled

y_value/y_max ordinate minimum/maximum..scaled

Destroy: No meaning

Input: Only valid for button 1 (left mouse) down)
x_value abscissa value of cursor position
y_value ordinate value of cursor position.

Normally there is no need to handle expose or resize, as the widget does all necessay things itself, but sometimes, it might be useful to react on resize, p.e. rescaling the plot.
 
 

Resources, that must be set:

There is no possibility to create a plot without having any scale, so these resources must be set at creation, they might be changed during lifetime.The only method to set them is using SetValue, as they need an array of four float values. The first pair d efines the abscissa, the second the ordinate. XwNezdrawScale uses the first value as the minimum value of the visible area and the second as the size(width/height) of visible area. Internally it scales the total pixmap according to these values. XwNezdrawG ridScale uses the first value as the minimum (first) grid value and the second as distance to next gridline. Again, not only the visible, but the total pixmap will be gridded.

Resources, that should be set:

This resources defines the position of annotation, the default is set to the standard, i.e. left and down. The value is a sum of definitions for horizontal and vertical. Changing the resource at run-time will change the display immediately.

Possible values:
XwEzdrawLeAnno 2 /* annotation left */
XwEzdrawRiAnno 4 /* annotation right */
XwEzdrawUpAnno 8 /* annotation above plot */
XwEzdrawDoAnno 16 /* annotation below plot */
XwEzdrawNoAnno 0 /* No annotation */

XwNezdrawAnnotXNdec XwNezdrawAnnotYNdec

These two control the number of decimals for annotation. Be careful and reduce them to a minimum, as there is no protection against overwriting of numbers. Together with the GridScale it might happen, that the annotation distance is to small for big number s, therefor the next two resources allow to skip some gridlines without drawing annotation.

XwNezdrawAnnotXNgrid XwNezdrawAnnotYNgrid

As the default of 1 shows, they define, how often annotation should be plotted to gridlines. So a value of 2 will say, that every other gridline gets annotation.

Additional controlling Resources:

The colour of the curve itself must be set via a public function, as each curve may have a different colour. But all other colours, background, grid, annotation and annotation background may be set as resource.

Resource	Function	default	Remark
XwNezdrawCUcolor	Background colour of the plotting area	Inherited from background	No immediate change
XwNezdrawAnnotColor	Colour for Annotation text	Inherited from foreground	No immediate change
XwNezdrawGridColor	Colour for the gridlines	Inherited from foreground	No immediate change
background	Background colour		No immediate change

 

As the above colours won't change immediately whe you change the resource, but will be effective only when a total redraw is enforced, the colour of the curve can be changed via a public function, the colourchange will affect the new plotted points only, a s long as no enforced redraw will happen.

XwNezdrawAddvalue XwNezdrawAddtext

XwNezdrawAddvalue is a switch, if it is set to true, the actual plotted point will be displayed with ist numeric values as a pair of ordinate/abscissa values, using the font and colour of annotation.

XwNezdrawAddtext is a string that will be displayed in the upper left corner of the plotting area. In addition to this text, a curve specific text (using the colour of specified curve) can be added using a public function.

HISTORY and PIXMAP-size:

XwNezdrawPixFactor

The default is set to 1, So the internal pixmap is as big as the visible area. Of course dragging doen't make any sense, resizing requires a replotting (if history enabled) or looses information. This resource is defined as a factor, saying the pixmap is X wNezdrawPixFactor times bigger than the visible area.. The visible area will be initiated in the middle of the pixmap. A dynamic change at run time will enforce a recreate and replot from history.

XwNezdrawHistory XwNezdrawHistorysize

The first is just a switch, enabling the ring-buffer. Ist default size is calculated from feight times width divided by 20. So normally this size is big enough to hold a lot of points.Using XwNezdrawHistorysize gives a lot more control over the number of p oints, that can be stored.
 
 

XwNezdrawAutoscroll

Together with a pixmap bigger than the visible area it is possible to enforce the visible area to show the last plotted point. If the resource is set to XwEzdrawAutoMove (2), plotting a point outside the visible area will immediately move the area to show the point. Another automatic option is XwCEzdrawAutoScal (1), this option will change the scaling by 1.25, rescale and redraw all. These two option may be combined by adding.

XwNezdrawBorder

draws a border in foreground colour around the plotting area.
 
 

Public Functions

XwEzdrawAddcurve

To use the plotting feature this function must be called first of all after creating the widget. It defines the colour of the requested curve and allocates memory for it. The return value should be used as curve ID for further access of this particular cur ve. It will be automatically created and counts from zero, so the first ID is 0.
 
 

XwEzdrawcurve

The basic function for plotting. It adds a point to the curve given by it's ID and plots it depending on flag. The parameter symbol is used, if symbol mode is requested. It defines the symbol out of 32 possible symbols. As it might be, that a hardcopy is n eeded, the symboldefinition is synchronized with the definitions of PS-plot system.

flag: basically, an odd value forces immediate display on screen.

XwEzdrawLinePlot (2) connects the actual point to previous with solid line

XwEzdrawSymbPlot (4) plots the point using the given symbol

XwEzdrawCharPlot(8) plots the point using the given character (character is centered), not plotting the corresponding symbol

XwEzdrawMovePlot(16)  moves to the actual point without any connection to previous

both values may be added, giving a combination, adding a 1 will immediately force display, but without this forcing, no display will appear at all until a force is given.

The array xy[2] must contain the coordinate values x and y for plotting.

Symbol definitions: (plotted in a 6x6 pixel matrix)

Value	Letter alias	description
1	A	rectangle
2	J	Filled rectangle
3	B	circle
4	K	Filled circle
5	C	Triangle pointing up
6	L	Filled triangle pointing up
7	D	Triangle pointing down
8	M	Filled triangle pointing down
9	E	Triangle pointing left
10	N	Filled triangle pointing left
11	F	Triangle pointing right
12	O	Filled triangle pointing right
13	G	Diamond
14	P	Filled diamond
15	H	Double triangle vertical
16	Q	Filled double triangle vertical
17	I	Double triangle horizontal
18	R	Filled double triangle horizontal
19	S	Diagonal cross (X)
20
21	T	Vertical cross (+)
22
23	U	Star (diagonal and vertical cross)
24
25	V	Rectangle with diagonal cross
26
27	W	Rectangle with vertical cross
28
29	X	Circle with diagonal cross
30
31	Y	Circle with vertical cross
32
33	Z	Diamond with vertical cross

If any options of XwNezdrawAutoscroll are enabled, these will be checked and executed, so moving the visible area or rescaling.

XwCreateEzdraw

Just a conveniance function for creating a Ezdraw Widget.

XwEzdrawClear

Sometimes there is a need to wipe out all previous drawing. This functions clears all plotted curves, resets the history and redisplays the cleared area.
If flag is zero, the cleared area is redisplayed, else only the internal pixmap is cleared and redisplay is done with the next plotting.
 

XwEzdrawSettext

The given text will be displayed in the upper left corner of the visible area, using the curve's colout. If there are more annotions to this edge, they are lined up. An empty text (or a NULL pointer) will delete the curve's text display. There is a small p roblem together with this text. If the update rate of display is high, the displayed text will flicker.

XwEzdrawchangecolor

Thie function changes the colour for the particular curve. So from now, all points plotted appear in new colour, all elder points will still have the old colour until a history redraw is done. Text and marker values will change colour immediately.

XwEzdrawhistory

Sometimes there is a need to get all plotted information back to memory. For example to do a hardcopy. If the history option (XwNezdrawHistory) is enabled, this function will allocate (malloc) three array, copy the internal history into them and return the addresses together with the number of items. The user is responsible to free the memory after usage.
 
 

Examples:

float scal[4] = {-15.0,30.0,-15.0,30.0};

float grid[4] = {-15.0,3.0,-15.0,3.0};
 
 
 
 

n = 0;

XtSetArg(args[n], XmNx, 486); n++;

XtSetArg(args[n], XmNy, 40); n++;

XtSetArg(args[n], XmNwidth, 252); n++;

XtSetArg(args[n], XmNheight, 352); n++;

EZ_userWidget10 = XtCreateWidget("userWidget10", XwEzdrawWidgetClass, EZ, args, n);

XtManageChild(EZ_userWidget10);

/* the following setting of scale and grid could be better done at creation, so move the XtSetArg prior to XtCreateWidget */

n = 0;

XtSetArg(args[n],XwNezdrawScale, scal); n++;

XtSetArg(args[n],XwNezdrawGridScale, grid); n++;

XtSetValues(EZ_userWidget10,args,n);
 
 

/* now add two curves The returned ID is know as 0 and 1, so no need to store */

XwEzdrawAddcurve(EZ_userWidget10, MGetPixel("red",EZ_userWidget10 ));
 
 

XwEzdrawAddcurve(EZ_userWidget10, MGetPixel("blue",EZ_userWidget10 ));
 
 

/* adding callbacks */

XtAddCallback(EZ_userWidget10, XmNresizeCallback, (XtCallbackProc) ezres_cb, (XtPointer)NULL);

XtAddCallback(EZ_userWidget10, XmNinputCallback, (XtCallbackProc) input_cb, (XtPointer)NULL);

XtAddCallback(EZ_userWidget10, XmNexposeCallback, (XtCallbackProc) ezexp_cb, (XtPointer)NULL);
 
 

}
 
 

{

float xy[2] ,xy1[2];

float radius = 10.0 , base = 0.0;

xy1[0] =radius * cos( base);

xy[0] = (radius+0.001) * sin(base);

xy[1] = (radius+0.001) * cos(base);

xy1[1] = radius*sin(base);
 
 

/* two curve points plotted, the first including a symbol, the second curve with display enforcing */

XwEzdrawcurve (EZ_userWidget10 , 0 , xy1 , 2 + XwEzdrawSymbPlot , 2);

XwEzdrawcurve (EZ_userWidget10 , 1 , xy , 1 , 0);
 
 

}

Table of contents

Description: 1

Example of a standard drawing: 1

Resources: 1

Detailed Description of special Resources: 2

Callbacks: 2

Resources, that must be set: 3

Resources, that should be set: 3

Additional controlling Resources: 3

HISTORY and PIXMAP-size: 4

Public Functions 4

XwEzdrawAddcurve 4

XwEzdrawcurve 5

XwCreateEzdraw 6

XwEzdrawClear 6

XwEzdrawSettext 6

XwEzdrawchangecolor 6

XwEzdrawhistory 6

Examples: 6