1GD::Simple(3) User Contributed Perl Documentation GD::Simple(3)
2
6 GD::Simple - Simplified interface to GD library
7
9 use GD::Simple;
10 # create a new image
12 $img = GD::Simple->new(400,250);
13 # draw a red rectangle with blue borders
15 $img->bgcolor('red');
16 $img->fgcolor('blue');
17 $img->rectangle(10,10,50,50);
18 # draw an empty rectangle with green borders
20 $img->bgcolor(undef);
21 $img->fgcolor('green');
22 $img->rectangle(30,30,100,100);
23 # move to (80,80) and draw a green line to (100,190)
25 $img->moveTo(80,80);
26 $img->lineTo(100,190);
27 # draw a solid orange ellipse
29 $img->moveTo(110,100);
30 $img->bgcolor('orange');
31 $img->fgcolor('orange');
32 $img->ellipse(40,40);
33 # draw a black filled arc
35 $img->moveTo(150,150);
36 $img->fgcolor('black');
37 $img->arc(50,50,0,100,gdNoFill|gdEdged);
38 # draw a string at (10,180) using the default
40 # built-in font
41 $img->moveTo(10,180);
42 $img->string('This is very simple');
43 # draw a string at (280,210) using 20 point
45 # times italic, angled upward 90 degrees
46 $img->moveTo(280,210);
47 $img->font('Times:italic');
48 $img->fontsize(20);
49 $img->angle(-90);
50 $img->string('This is very fancy');
51 # some turtle graphics
53 $img->moveTo(300,100);
54 $img->penSize(3,3);
55 $img->angle(0);
56 $img->line(20); # 20 pixels going to the right
57 $img->turn(30); # set turning angle to 30 degrees
58 $img->line(20); # 20 pixel line
59 $img->line(20);
60 $img->line(20);
61 $img->turn(-90); # set turning angle to -90 degrees
62 $img->line(50); # 50 pixel line
63 # draw a cyan polygon edged in blue
65 my $poly = new GD::Polygon;
66 $poly->addPt(150,100);
67 $poly->addPt(199,199);
68 $poly->addPt(100,199);
69 $img->bgcolor('cyan');
70 $img->fgcolor('blue');
71 $img->penSize(1,1);
72 $img->polygon($poly);
73 # convert into png data
75 print $img->png;
76
78 GD::Simple is a subclass of the GD library that shortens many of the
79 long GD method calls by storing information about the pen color, size
80 and position in the GD object itself. It also adds a small number of
81 "turtle graphics" style calls for those who prefer to work in polar
82 coordinates. In addition, the library allows you to use symbolic names
83 for colors, such as "chartreuse", and will manage the colors for you.
84 The Pen
86 GD::Simple maintains a "pen" whose settings are used for line- and
87 shape-drawing operations. The pen has the following properties:
88 fgcolor
90 The pen foreground color is the color of lines and the borders of
91 filled and unfilled shapes.
92 bgcolor
94 The pen background color is the color of the contents of filled
95 shapes.
96 pensize
98 The pen size is the width of the pen. Larger sizes draw thicker
99 lines.
100 position
102 The pen position is its current position on the canvas in (X,Y)
103 coordinates.
104 angle
106 When drawing in turtle mode, the pen angle determines the current
107 direction of lines of relative length.
108 turn
110 When drawing in turtle mode, the turn determines the clockwise or
111 counterclockwise angle that the pen will turn before drawing the
112 next line.
113 font
115 The font to use when drawing text. Both built-in bitmapped fonts
116 and TrueType fonts are supported.
117 fontsize
119 The size of the font to use when drawing with TrueType fonts.
120 One sets the position and properties of the pen and then draws. As the
122 drawing progresses, the position of the pen is updated.
123 Methods
125 GD::Simple introduces a number of new methods, a few of which have the
126 same name as GD::Image methods, and hence change their behavior. In
127 addition to these new methods, GD::Simple objects support all of the
128 GD::Image methods. If you make a method call that isn't directly
129 supported by GD::Simple, it refers the request to the underlying
130 GD::Image object. Hence one can load a JPEG image into GD::Simple and
131 declare it to be TrueColor by using this call, which is effectively
132 inherited from GD::Image:
133 my $img = GD::Simple->newFromJpeg('./myimage.jpg',1);
135 The rest of this section describes GD::Simple-specific methods.
137 $img = GD::Simple->new($x,$y [,$truecolor])
139 $img = GD::Simple->new($gd)
140 Create a new GD::Simple object. There are two forms of new(). In
141 the first form, pass the width and height of the desired canvas,
142 and optionally a boolean flag to request a truecolor image. In the
143 second form, pass a previously-created GD::Image object.
144 GD::Simple->class('GD');
146 GD::Simple->class('GD::SVG');
147 Select whether new() should use GD or GD::SVG internally. Call
148 GD::Simple->class('GD::SVG') before calling new() if you wish to
149 generate SVG images.
150 If future GD subclasses are created, this method will subport them.
152 $img->moveTo($x,$y)
154 This call changes the position of the pen without drawing. It moves
155 the pen to position ($x,$y) on the drawing canvas.
156 $img->move($dx,$dy)
158 $img->move($dr)
159 This call changes the position of the pen without drawing. When
160 called with two arguments it moves the pen $dx pixels to the right
161 and $dy pixels downward. When called with one argument it moves
162 the pen $dr pixels along the vector described by the current pen
163 angle.
164 $img->lineTo($x,$y)
166 The lineTo() call simultaneously draws and moves the pen. It draws
167 a line from the current pen position to the position defined by
168 ($x,$y) using the current pen size and color. After drawing, the
169 position of the pen is updated to the new position.
170 $img->line($dx,$dy)
172 $img->line($dr)
173 The line() call simultaneously draws and moves the pen. When called
174 with two arguments it draws a line from the current position of the
175 pen to the position $dx pixels to the right and $dy pixels down.
176 When called with one argument, it draws a line $dr pixels long
177 along the angle defined by the current pen angle.
178 $img->clear
180 This method clears the canvas by painting over it with the current
181 background color.
182 $img->rectangle($x1,$y1,$x2,$y2)
184 This method draws the rectangle defined by corners ($x1,$y1),
185 ($x2,$y2). The rectangle's edges are drawn in the foreground color
186 and its contents are filled with the background color. To draw a
187 solid rectangle set bgcolor equal to fgcolor. To draw an unfilled
188 rectangle (transparent inside), set bgcolor to undef.
189 $img->ellipse($width,$height)
191 This method draws the ellipse centered at the current location with
192 width $width and height $height. The ellipse's border is drawn in
193 the foreground color and its contents are filled with the
194 background color. To draw a solid ellipse set bgcolor equal to
195 fgcolor. To draw an unfilled ellipse (transparent inside), set
196 bgcolor to undef.
197 $img->arc($cx,$cy,$width,$height,$start,$end [,$style])
199 This method draws filled and unfilled arcs. See GD for a
200 description of the arguments. To draw a solid arc (such as a pie
201 wedge) set bgcolor equal to fgcolor. To draw an unfilled arc, set
202 bgcolor to undef.
203 $img->polygon($poly)
205 This method draws filled and unfilled polygon using the current
206 settings of fgcolor for the polygon border and bgcolor for the
207 polygon fill color. See GD for a description of creating polygons.
208 To draw a solid polygon set bgcolor equal to fgcolor. To draw an
209 unfilled polygon, set bgcolor to undef.
210 $img->polyline($poly)
212 This method draws polygons without closing the first and last
213 vertices (similar to GD::Image->unclosedPolygon()). It uses the
214 fgcolor to draw the line.
215 $img->string($string)
217 This method draws the indicated string starting at the current
218 position of the pen. The pen is moved to the end of the drawn
219 string. Depending on the font selected with the font() method,
220 this will use either a bitmapped GD font or a TrueType font. The
221 angle of the pen will be consulted when drawing the text. For
222 TrueType fonts, any angle is accepted. For GD bitmapped fonts, the
223 angle can be either 0 (draw horizontal) or -90 (draw upwards).
224 For consistency between the TrueType and GD font behavior, the
226 string is always drawn so that the current position of the pen
227 corresponds to the bottom left of the first character of the text.
228 This is different from the GD behavior, in which the first
229 character of bitmapped fonts hangs down from the pen point.
230 This method returns a polygon indicating the bounding box of the
232 rendered text. If an error occurred (such as invalid font
233 specification) it returns undef and an error message in $@.
234 $metrics = $img->fontMetrics
236 ($metrics,$width,$height) =
237 GD::Simple->fontMetrics($font,$fontsize,$string)
238 This method returns information about the current font, most
239 commonly a TrueType font. It can be invoked as an instance method
240 (on a previously-created GD::Simple object) or as a class method
241 (on the 'GD::Simple' class).
242 When called as an instance method, fontMetrics() takes no arguments
244 and returns a single hash reference containing the metrics that
245 describe the currently selected font and size. The hash reference
246 contains the following information:
247 xheight the base height of the font from the bottom to the top of
249 a lowercase 'm'
250 ascent the length of the upper stem of the lowercase 'd'
252 descent the length of the lower step of the lowercase 'j'
254 lineheight the distance from the bottom of the 'j' to the top of
256 the 'd'
257 leading the distance between two adjacent lines
259 ($delta_x,$delta_y)= $img->stringBounds($string)
261 This method indicates the X and Y offsets (which may be negative)
262 that will occur when the given string is drawn using the current
263 font, fontsize and angle. When the string is drawn horizontally, it
264 gives the width and height of the string's bounding box.
265 $delta_x = $img->stringWidth($string)
267 This method indicates the width of the string given the current
268 font, fontsize and angle. It is the same as
269 ($img->stringBounds($string))[0]
270 ($x,$y) = $img->curPos
272 Return the current position of the pen. Set the current position
273 using moveTo().
274 $font = $img->font([$newfont] [,$newsize])
276 Get or set the current font. Fonts can be GD::Font objects,
277 TrueType font file paths, or fontconfig font patterns like
278 "Times:italic" (see fontconfig). The latter feature requires that
279 you have the fontconfig library installed and are using libgd
280 version 2.0.33 or higher.
281 As a shortcut, you may pass two arguments to set the font and the
283 fontsize simultaneously. The fontsize is only valid when drawing
284 with TrueType fonts.
285 $size = $img->fontsize([$newfontsize])
287 Get or set the current font size. This is only valid for TrueType
288 fonts.
289 $size = $img->penSize([$newpensize])
291 Get or set the current pen width for use during line drawing
292 operations.
293 $angle = $img->angle([$newangle])
295 Set the current angle for use when calling line() or move() with a
296 single argument.
297 Here is an example of using turn() and angle() together to draw an
299 octagon. The first line drawn is the downward-slanting top right
300 edge. The last line drawn is the horizontal top of the octagon.
301 $img->moveTo(200,50);
303 $img->angle(0);
304 $img->turn(360/8);
305 for (1..8) { $img->line(50) }
306 $angle = $img->turn([$newangle])
308 Get or set the current angle to turn prior to drawing lines. This
309 value is only used when calling line() or move() with a single
310 argument. The turning angle will be applied to each call to line()
311 or move() just before the actual drawing occurs.
312 Angles are in degrees. Positive values turn the angle clockwise.
314 $color = $img->fgcolor([$newcolor])
316 Get or set the pen's foreground color. The current pen color can
317 be set by (1) using an (r,g,b) triple; (2) using a previously-
318 allocated color from the GD palette; or (3) by using a symbolic
319 color name such as "chartreuse." The list of color names can be
320 obtained using color_names(). The special color name 'transparent'
321 will create a completely transparent color.
322 $color = $img->bgcolor([$newcolor])
324 Get or set the pen's background color. The current pen color can
325 be set by (1) using an (r,g,b) triple; (2) using a previously-
326 allocated color from the GD palette; or (3) by using a symbolic
327 color name such as "chartreuse." The list of color names can be
328 obtained using color_names(). The special color name 'transparent'
329 will create a completely transparent color.
330 $index = $img->translate_color(@args)
332 Translates a color into a GD palette or TrueColor index. You may
333 pass either an (r,g,b) triple or a symbolic color name. If you pass
334 a previously-allocated index, the method will return it unchanged.
335 $index = $img->alphaColor(@args,$alpha)
337 Creates an alpha color. You may pass either an (r,g,b) triple or a
338 symbolic color name, followed by an integer indicating its opacity.
339 The opacity value ranges from 0 (fully opaque) to 127 (fully
340 transparent).
341 @names = GD::Simple->color_names
343 $translate_table = GD::Simple->color_names
344 Called in a list context, color_names() returns the list of
345 symbolic color names recognized by this module. Called in a scalar
346 context, the method returns a hash reference in which the keys are
347 the color names and the values are array references containing
348 [r,g,b] triples.
349 $gd = $img->gd
351 Return the internal GD::Image object. Usually you will not need to
352 call this since all GD methods are automatically referred to this
353 object.
354 ($red,$green,$blue) = GD::Simple->HSVtoRGB($hue,$saturation,$value)
356 Convert a Hue/Saturation/Value (HSV) color into an RGB triple. The
357 hue, saturation and value are integers from 0 to 255.
358 ($hue,$saturation,$value) =
360 GD::Simple->RGBtoHSV($hue,$saturation,$value)
361 Convert a Red/Green/Blue (RGB) value into a Hue/Saturation/Value
362 (HSV) triple. The hue, saturation and value are integers from 0 to
363 255.
364
366 This script will create an image showing all the symbolic colors.
367 #!/usr/bin/perl
369 use strict;
371 use GD::Simple;
372 my @color_names = GD::Simple->color_names;
374 my $cols = int(sqrt(@color_names));
375 my $rows = int(@color_names/$cols)+1;
376 my $cell_width = 100;
378 my $cell_height = 50;
379 my $legend_height = 16;
380 my $width = $cols * $cell_width;
381 my $height = $rows * $cell_height;
382 my $img = GD::Simple->new($width,$height);
384 $img->font(gdSmallFont);
385 for (my $c=0; $c<$cols; $c++) {
387 for (my $r=0; $r<$rows; $r++) {
388 my $color = $color_names[$c*$rows + $r] or next;
389 my @topleft = ($c*$cell_width,$r*$cell_height);
390 my @botright = ($topleft[0]+$cell_width,$topleft[1]+$cell_height-$legend_height);
391 $img->bgcolor($color);
392 $img->fgcolor($color);
393 $img->rectangle(@topleft,@botright);
394 $img->moveTo($topleft[0]+2,$botright[1]+$legend_height-2);
395 $img->fgcolor('black');
396 $img->string($color);
397 }
398 }
399 print $img->png;
401
403 The GD::Simple module is copyright 2004, Lincoln D. Stein. It is
404 distributed under the same terms as Perl itself. See the "Artistic
405 License" in the Perl source code distribution for licensing terms.
406 The latest versions of GD.pm are available at
408 http://stein.cshl.org/WWW/software/GD
410
412 GD, GD::Polyline, GD::SVG, Image::Magick
413perl v5.12.0 2008-12-21 GD::Simple(3)