Provided by: libgd-perl_2.78-1build3_amd64 
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