Free Knowledge Resources


Linux Manual Pages


Free Software * Books

Source Code

Free Media

Linux

XDrawRectangle(3)


NAME

   XDrawRectangle, XDrawRectangles, XRectangle - draw rectangles and
   rectangles structure

SYNTAX

   int XDrawRectangle(Display *display, Drawable d, GC gc, int x, int y,
          unsigned int width, unsigned int height);

   int XDrawRectangles(Display *display, Drawable d, GC gc, XRectangle
          rectangles[], int nrectangles);

ARGUMENTS

   d         Specifies the drawable.

   display   Specifies the connection to the X server.

   gc        Specifies the GC.

   nrectangles
             Specifies the number of rectangles in the array.

   rectangles
             Specifies an array of rectangles.

   width
   height    Specify the width and height, which specify the dimensions of
             the rectangle.

   x
   y         Specify the x and y coordinates, which specify the upper-left
             corner of the rectangle.

DESCRIPTION

   The XDrawRectangle and XDrawRectangles functions draw the outlines of
   the specified rectangle or rectangles as if a five-point PolyLine
   protocol request were specified for each rectangle:

          [x,y] [x+width,y] [x+width,y+height] [x,y+height] [x,y]

   For the specified rectangle or rectangles, these functions do not draw
   a pixel more than once.  XDrawRectangles draws the rectangles in the
   order listed in the array.  If rectangles intersect, the intersecting
   pixels are drawn multiple times.

   Both functions use these GC components: function, plane-mask, line-
   width, line-style, cap-style, join-style, fill-style, subwindow-mode,
   clip-x-origin, clip-y-origin, and clip-mask.  They also use these GC
   mode-dependent components: foreground, background, tile, stipple, tile-
   stipple-x-origin, tile-stipple-y-origin, dash-offset, and dash-list.

   XDrawRectangle and XDrawRectangles can generate BadDrawable, BadGC, and
   BadMatch errors.

STRUCTURES

   The XRectangle structure contains:

   typedef struct {
           short x, y;
           unsigned short width, height;
   } XRectangle;

   All x and y members are signed integers.  The width and height members
   are 16-bit unsigned integers.  You should be careful not to generate
   coordinates and sizes out of the 16-bit ranges, because the protocol
   only has 16-bit fields for these values.

DIAGNOSTICS

   BadDrawable
             A value for a Drawable argument does not name a defined
             Window or Pixmap.

   BadGC     A value for a GContext argument does not name a defined
             GContext.

   BadMatch  An InputOnly window is used as a Drawable.

   BadMatch  Some argument or pair of arguments has the correct type and
             range but fails to match in some other way required by the
             request.

SEE ALSO

   XDrawArc(3), XDrawLine(3), XDrawPoint(3)
   Xlib - C Language X Interface



Opportunity


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.



Free Software


Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.



Free Books


The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.



Education


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.


birds banner