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GD::Simple(3)         User Contributed Perl Documentation        GD::Simple(3)



NAME

       GD::Simple - Simplified interface to GD library


SYNOPSIS

       For a nice tutorial on using this module, see Gabor Szabo's article at
       http://perlmaven.com/drawing-images-using-gd-simple.

           use GD::Simple;

           # create a new image
           $img = GD::Simple->new(400,250);

           # draw a red rectangle with blue borders
           $img->bgcolor('red');
           $img->fgcolor('blue');
           $img->rectangle(10,10,50,50);

           # draw an empty rectangle with green borders
           $img->bgcolor(undef);
           $img->fgcolor('green');
           $img->rectangle(30,30,100,100);

           # move to (80,80) and draw a green line to (100,190)
           $img->moveTo(80,80);
           $img->lineTo(100,190);

           # draw a solid orange ellipse
           $img->moveTo(110,100);
           $img->bgcolor('orange');
           $img->fgcolor('orange');
           $img->ellipse(40,40);

           # draw a black filled arc
           $img->moveTo(150,150);
           $img->fgcolor('black');
           $img->arc(50,50,0,100,gdNoFill|gdEdged);

           # draw a string at (10,180) using the default
           # built-in font
           $img->moveTo(10,180);
           $img->string('This is very simple');

           # draw a string at (280,210) using 20 point
           # times italic, angled upward 90 degrees
           $img->moveTo(280,210);
           $img->font('Times:italic');
           $img->fontsize(20);
           $img->angle(-90);
           $img->string('This is very fancy');

           # some turtle graphics
           $img->moveTo(300,100);
           $img->penSize(3,3);
           $img->angle(0);
           $img->line(20);   # 20 pixels going to the right
           $img->turn(30);   # set turning angle to 30 degrees
           $img->line(20);   # 20 pixel line
           $img->line(20);
           $img->line(20);
           $img->turn(-90); # set turning angle to -90 degrees
           $img->line(50);  # 50 pixel line

           # draw a cyan polygon edged in blue
           my $poly = GD::Polygon->new;
           $poly->addPt(150,100);
           $poly->addPt(199,199);
           $poly->addPt(100,199);
           $img->bgcolor('cyan');
           $img->fgcolor('blue');
           $img->penSize(1,1);
           $img->polygon($poly);

          # convert into png data
          print $img->png;


DESCRIPTION

       GD::Simple is a subclass of the GD library that shortens many of the
       long GD method calls by storing information about the pen color, size
       and position in the GD object itself.  It also adds a small number of
       "turtle graphics" style calls for those who prefer to work in polar
       coordinates.  In addition, the library allows you to use symbolic names
       for colors, such as "chartreuse", and will manage the colors for you.

   The Pen
       GD::Simple maintains a "pen" whose settings are used for line- and
       shape-drawing operations.  The pen has the following properties:

       fgcolor
           The pen foreground color is the color of lines and the borders of
           filled and unfilled shapes.

       bgcolor
           The pen background color is the color of the contents of filled
           shapes.

       pensize
           The pen size is the width of the pen.  Larger sizes draw thicker
           lines.

       position
           The pen position is its current position on the canvas in (X,Y)
           coordinates.

       angle
           When drawing in turtle mode, the pen angle determines the current
           direction of lines of relative length.

       turn
           When drawing in turtle mode, the turn determines the clockwise or
           counterclockwise angle that the pen will turn before drawing the
           next line.

       font
           The font to use when drawing text.  Both built-in bitmapped fonts
           and TrueType fonts are supported.

       fontsize
           The size of the font to use when drawing with TrueType fonts.

       One sets the position and properties of the pen and then draws.  As the
       drawing progresses, the position of the pen is updated.

   Methods
       GD::Simple introduces a number of new methods, a few of which have the
       same name as GD::Image methods, and hence change their behavior. In
       addition to these new methods, GD::Simple objects support all of the
       GD::Image methods. If you make a method call that isn't directly
       supported by GD::Simple, it refers the request to the underlying
       GD::Image object.  Hence one can load a JPEG image into GD::Simple and
       declare it to be TrueColor by using this call, which is effectively
       inherited from GD::Image:

         my $img = GD::Simple->newFromJpeg('./myimage.jpg',1);

       The rest of this section describes GD::Simple-specific methods.

       $img = GD::Simple->new($x,$y [,$truecolor])
       $img = GD::Simple->new($gd)
           Create a new GD::Simple object. There are two forms of new(). In
           the first form, pass the width and height of the desired canvas,
           and optionally a boolean flag to request a truecolor image. In the
           second form, pass a previously-created GD::Image object.

       GD::Simple->class('GD');
       GD::Simple->class('GD::SVG');
           Select whether new() should use GD or GD::SVG internally. Call
           GD::Simple->class('GD::SVG') before calling new() if you wish to
           generate SVG images.

           If future GD subclasses are created, this method will subport them.

       $img->moveTo($x,$y)
           This call changes the position of the pen without drawing. It moves
           the pen to position ($x,$y) on the drawing canvas.

       $img->move($dx,$dy)
       $img->move($dr)
           This call changes the position of the pen without drawing. When
           called with two arguments it moves the pen $dx pixels to the right
           and $dy pixels downward.  When called with one argument it moves
           the pen $dr pixels along the vector described by the current pen
           angle.

       $img->lineTo($x,$y)
           The lineTo() call simultaneously draws and moves the pen.  It draws
           a line from the current pen position to the position defined by
           ($x,$y) using the current pen size and color.  After drawing, the
           position of the pen is updated to the new position.

       $img->line($x1,$y1,$x2,$y2 [,$color])
       $img->line($dx,$dy)
       $img->line($dr)
           The line() call simultaneously draws and moves the pen. When called
           with two arguments it draws a line from the current position of the
           pen to the position $dx pixels to the right and $dy pixels down.
           When called with one argument, it draws a line $dr pixels long
           along the angle defined by the current pen angle.

           When called with four or five arguments, line() behaves like
           GD::Image->line().

       $img->clear
           This method clears the canvas by painting over it with the current
           background color.

       $img->rectangle($x1,$y1,$x2,$y2)
           This method draws the rectangle defined by corners ($x1,$y1),
           ($x2,$y2). The rectangle's edges are drawn in the foreground color
           and its contents are filled with the background color. To draw a
           solid rectangle set bgcolor equal to fgcolor. To draw an unfilled
           rectangle (transparent inside), set bgcolor to undef.

       $img->ellipse($width,$height)
           This method draws the ellipse centered at the current location with
           width $width and height $height.  The ellipse's border is drawn in
           the foreground color and its contents are filled with the
           background color. To draw a solid ellipse set bgcolor equal to
           fgcolor. To draw an unfilled ellipse (transparent inside), set
           bgcolor to undef.

       $img->arc([$cx,$cy,] $width,$height,$start,$end [,$style])
           This method draws filled and unfilled arcs, at the current
           position, with the current fore- and background colors.  See GD for
           a description of the arguments. To draw a solid arc (such as a pie
           wedge) set bgcolor equal to fgcolor. To draw an unfilled arc, set
           bgcolor to undef.

       $img->polygon($poly)
           This method draws filled and unfilled polygon using the current
           settings of fgcolor for the polygon border and bgcolor for the
           polygon fill color.  See GD for a description of creating polygons.
           To draw a solid polygon set bgcolor equal to fgcolor. To draw an
           unfilled polygon, set bgcolor to undef.

       $img->polyline($poly)
           This method draws polygons without closing the first and last
           vertices (similar to GD::Image->unclosedPolygon()). It uses the
           fgcolor to draw the line.

       $img->string($string)
           This method draws the indicated string starting at the current
           position of the pen. The pen is moved to the end of the drawn
           string.  Depending on the font selected with the font() method,
           this will use either a bitmapped GD font or a TrueType font.  The
           angle of the pen will be consulted when drawing the text. For
           TrueType fonts, any angle is accepted.  For GD bitmapped fonts, the
           angle can be either 0 (draw horizontal) or -90 (draw upwards).

           For consistency between the TrueType and GD font behavior, the
           string is always drawn so that the current position of the pen
           corresponds to the bottom left of the first character of the text.
           This is different from the GD behavior, in which the first
           character of bitmapped fonts hangs down from the pen point.

           This method returns a polygon indicating the bounding box of the
           rendered text.  If an error occurred (such as invalid font
           specification) it returns undef and an error message in $@.

       $metrics = $img->fontMetrics
       ($metrics,$width,$height) =
       GD::Simple->fontMetrics($font,$fontsize,$string)
           This method returns information about the current font, most
           commonly a TrueType font. It can be invoked as an instance method
           (on a previously-created GD::Simple object) or as a class method
           (on the 'GD::Simple' class).

           When called as an instance method, fontMetrics() takes no arguments
           and returns a single hash reference containing the metrics that
           describe the currently selected font and size. The hash reference
           contains the following information:

             xheight      the base height of the font from the bottom to the top of
                          a lowercase 'm'

             ascent       the length of the upper stem of the lowercase 'd'

             descent      the length of the lower step of the lowercase 'j'

             lineheight   the distance from the bottom of the 'j' to the top of
                          the 'd'

             leading      the distance between two adjacent lines

           This description and code was changed with 2.75.

       ($delta_x,$delta_y)= $img->stringBounds($string)
           This method indicates the X and Y offsets (which may be negative)
           that will occur when the given string is drawn using the current
           font, fontsize and angle. When the string is drawn horizontally, it
           gives the width and height of the string's bounding box.

       $delta_x = $img->stringWidth($string)
           This method indicates the width of the string given the current
           font, fontsize and angle. It is the same as
           ($img->stringBounds($string))[0]

       ($x,$y) = $img->curPos
           Return the current position of the pen.  Set the current position
           using moveTo().

       $font = $img->font([$newfont] [,$newsize])
           Get or set the current font.  Fonts can be GD::Font objects,
           TrueType font file paths, or fontconfig font patterns like
           "Times:italic" (see fontconfig). The latter feature requires that
           you have the fontconfig library installed and are using libgd
           version 2.0.33 or higher.

           As a shortcut, you may pass two arguments to set the font and the
           fontsize simultaneously. The fontsize is only valid when drawing
           with TrueType fonts.

       $size = $img->fontsize([$newfontsize])
           Get or set the current font size.  This is only valid for TrueType
           fonts.

       $size = $img->penSize([$newpensize])
           Get or set the current pen width for use during line drawing
           operations.

       $angle = $img->angle([$newangle])
           Set the current angle for use when calling line() or move() with a
           single argument.

           Here is an example of using turn() and angle() together to draw an
           octagon.  The first line drawn is the downward-slanting top right
           edge.  The last line drawn is the horizontal top of the octagon.

             $img->moveTo(200,50);
             $img->angle(0);
             $img->turn(360/8);
             for (1..8) { $img->line(50) }

       $angle = $img->turn([$newangle])
           Get or set the current angle to turn prior to drawing lines.  This
           value is only used when calling line() or move() with a single
           argument.  The turning angle will be applied to each call to line()
           or move() just before the actual drawing occurs.

           Angles are in degrees.  Positive values turn the angle clockwise.

       $color = $img->fgcolor([$newcolor])
           Get or set the pen's foreground color.  The current pen color can
           be set by (1) using an (r,g,b) triple; (2) using a previously-
           allocated color from the GD palette; or (3) by using a symbolic
           color name such as "chartreuse."  The list of color names can be
           obtained using color_names(). The special color name 'transparent'
           will create a completely transparent color.

       $color = $img->bgcolor([$newcolor])
           Get or set the pen's background color.  The current pen color can
           be set by (1) using an (r,g,b) triple; (2) using a previously-
           allocated color from the GD palette; or (3) by using a symbolic
           color name such as "chartreuse."  The list of color names can be
           obtained using color_names(). The special color name 'transparent'
           will create a completely transparent color.

       $index = $img->translate_color(@args)
           Translates a color into a GD palette or TrueColor index.  You may
           pass either an (r,g,b) triple or a symbolic color name. If you pass
           a previously-allocated index, the method will return it unchanged.

       $index = $img->alphaColor(@args,$alpha)
           Creates an alpha color.  You may pass either an (r,g,b) triple or a
           symbolic color name, followed by an integer indicating its opacity.
           The opacity value ranges from 0 (fully opaque) to 127 (fully
           transparent).

       @names = GD::Simple->color_names
       $translate_table = GD::Simple->color_names
           Called in a list context, color_names() returns the list of
           symbolic color names recognized by this module.  Called in a scalar
           context, the method returns a hash reference in which the keys are
           the color names and the values are array references containing
           [r,g,b] triples.

       $gd = $img->gd
           Return the internal GD::Image object.  Usually you will not need to
           call this since all GD methods are automatically referred to this
           object.

       ($red,$green,$blue) = GD::Simple->HSVtoRGB($hue,$saturation,$value)
           Convert a Hue/Saturation/Value (HSV) color into an RGB triple. The
           hue, saturation and value are integers from 0 to 255.

       ($hue,$saturation,$value) = GD::Simple->RGBtoHSV($red,$green,$blue)
           Convert a Red/Green/Blue (RGB) value into a Hue/Saturation/Value
           (HSV) triple. The hue, saturation and value are integers from 0 to
           255.


COLORS

       This script will create an image showing all the symbolic colors.

        #!/usr/bin/perl

        use strict;
        use GD::Simple;

        my @color_names = GD::Simple->color_names;
        my $cols = int(sqrt(@color_names));
        my $rows = int(@color_names/$cols)+1;

        my $cell_width    = 100;
        my $cell_height   = 50;
        my $legend_height = 16;
        my $width       = $cols * $cell_width;
        my $height      = $rows * $cell_height;

        my $img = GD::Simple->new($width,$height);
        $img->font(gdSmallFont);

        for (my $c=0; $c<$cols; $c++) {
          for (my $r=0; $r<$rows; $r++) {
            my $color = $color_names[$c*$rows + $r] or next;
            my @topleft  = ($c*$cell_width,$r*$cell_height);
            my @botright = ($topleft[0]+$cell_width,$topleft[1]+$cell_height-$legend_height);
            $img->bgcolor($color);
            $img->fgcolor($color);
            $img->rectangle(@topleft,@botright);
            $img->moveTo($topleft[0]+2,$botright[1]+$legend_height-2);
            $img->fgcolor('black');
            $img->string($color);
          }
        }

        print $img->png;


AUTHOR

       The GD::Simple module is copyright 2004, Lincoln D. Stein.  It is
       distributed under the same terms as Perl itself.  See the "Artistic
       License" in the Perl source code distribution for licensing terms.

       The latest versions of GD.pm are available at
       https://github.com/lstein/Perl-GD


SEE ALSO

       GD, GD::Polyline, GD::SVG, Image::Magick

perl v5.34.1                      2022-01-26                     GD::Simple(3)

gd 2.780.0 - Generated Mon Aug 28 19:19:31 CDT 2023
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