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
88 shape-drawing operations. The pen has the following properties:
89 fgcolor
91 The pen foreground color is the color of lines and the borders of
92 filled and unfilled shapes.
93 bgcolor
95 The pen background color is the color of the contents of filled
96 shapes.
97 pensize
99 The pen size is the width of the pen. Larger sizes draw thicker
100 lines.
101 position
103 The pen position is its current position on the canvas in (X,Y)
104 coordinates.
105 angle
107 When drawing in turtle mode, the pen angle determines the current
108 direction of lines of relative length.
109 turn
111 When drawing in turtle mode, the turn determines the clockwise or
112 counterclockwise angle that the pen will turn before drawing the
113 next line.
114 font
116 The font to use when drawing text. Both built-in bitmapped fonts
117 and TrueType fonts are supported.
118 fontsize
120 The size of the font to use when drawing with TrueType fonts.
121 One sets the position and properties of the pen and then draws. As the
123 drawing progresses, the position of the pen is updated.
124 Methods
126 GD::Simple introduces a number of new methods, a few of which have the
128 same name as GD::Image methods, and hence change their behavior. In
129 addition to these new methods, GD::Simple objects support all of the
130 GD::Image methods. If you make a method call that isn't directly sup‐
131 ported by GD::Simple, it refers the request to the underlying GD::Image
132 object. Hence one can load a JPEG image into GD::Simple and declare it
133 to be TrueColor by using this call, which is effectively inherited from
134 GD::Image:
135 my $img = GD::Simple->newFromJpeg('./myimage.jpg',1);
137 The rest of this section describes GD::Simple-specific methods.
139 $img->moveTo($x,$y)
141 This call changes the position of the pen without drawing. It moves
142 the pen to position ($x,$y) on the drawing canvas.
143 $img->move($dx,$dy)
145 $img->move($dr)
146 This call changes the position of the pen without drawing. When
147 called with two arguments it moves the pen $dx pixels to the right
148 and $dy pixels downward. When called with one argument it moves
149 the pen $dr pixels along the vector described by the current pen
150 angle.
151 $img->lineTo($x,$y)
153 The lineTo() call simultaneously draws and moves the pen. It draws
154 a line from the current pen position to the position defined by
155 ($x,$y) using the current pen size and color. After drawing, the
156 position of the pen is updated to the new position.
157 $img->line($dx,$dy)
159 $img->line($dr)
160 The line() call simultaneously draws and moves the pen. When called
161 with two arguments it draws a line from the current position of the
162 pen to the position $dx pixels to the right and $dy pixels down.
163 When called with one argument, it draws a line $dr pixels long
164 along the angle defined by the current pen angle.
165 $img->clear
167 This method clears the canvas by painting over it with the current
168 background color.
169 $img->rectangle($x1,$y1,$x2,$y2)
171 This method draws the rectangle defined by corners ($x1,$y1),
172 ($x2,$y2). The rectangle's edges are drawn in the foreground color
173 and its contents are filled with the background color. To draw a
174 solid rectangle set bgcolor equal to fgcolor. To draw an unfilled
175 rectangle (transparent inside), set bgcolor to undef.
176 $img->ellipse($width,$height)
178 This method draws the ellipse centered at the current location with
179 width $width and height $height. The ellipse's border is drawn in
180 the foreground color and its contents are filled with the back‐
181 ground color. To draw a solid ellipse set bgcolor equal to fgcolor.
182 To draw an unfilled ellipse (transparent inside), set bgcolor to
183 undef.
184 $img->arc($cx,$cy,$width,$height,$start,$end [,$style])
186 This method draws filled and unfilled arcs. See GD for a descrip‐
187 tion of the arguments. To draw a solid arc (such as a pie wedge)
188 set bgcolor equal to fgcolor. To draw an unfilled arc, set bgcolor
189 to undef.
190 $img->polygon($poly)
192 This method draws filled and unfilled polygon using the current
193 settings of fgcolor for the polygon border and bgcolor for the
194 polygon fill color. See GD for a description of creating polygons.
195 To draw a solid polygon set bgcolor equal to fgcolor. To draw an
196 unfilled polygon, set bgcolor to undef.
197 $img->polyline($poly)
199 This method draws polygons without closing the first and last ver‐
200 tices (similar to GD::Image->unclosedPolygon()). It uses the
201 fgcolor to draw the line.
202 $img->string($string)
204 This method draws the indicated string starting at the current
205 position of the pen. The pen is moved to the end of the drawn
206 string. Depending on the font selected with the font() method,
207 this will use either a bitmapped GD font or a TrueType font. The
208 angle of the pen will be consulted when drawing the text. For True‐
209 Type fonts, any angle is accepted. For GD bitmapped fonts, the
210 angle can be either 0 (draw horizontal) or -90 (draw upwards).
211 For consistency between the TrueType and GD font behavior, the
213 string is always drawn so that the current position of the pen cor‐
214 responds to the bottom left of the first character of the text.
215 This is different from the GD behavior, in which the first charac‐
216 ter of bitmapped fonts hangs down from the pen point.
217 This method returns a polygon indicating the bounding box of the
219 rendered text. If an error occurred (such as invalid font specifi‐
220 cation) it returns undef and an error message in $@.
221 $metrics = $img->fontMetrics
223 ($metrics,$width,$height) = GD::Simple->fontMetrics($font,$font‐
224 size,$string)
225 This method returns information about the current font, most com‐
226 monly a TrueType font. It can be invoked as an instance method (on
227 a previously-created GD::Simple object) or as a class method (on
228 the 'GD::Simple' class).
229 When called as an instance method, fontMetrics() takes no arguments
231 and returns a single hash reference containing the metrics that
232 describe the currently selected font and size. The hash reference
233 contains the following information:
234 xheight the base height of the font from the bottom to the top of
236 a lowercase 'm'
237 ascent the length of the upper stem of the lowercase 'd'
239 descent the length of the lower step of the lowercase 'j'
241 lineheight the distance from the bottom of the 'j' to the top of
243 the 'd'
244 leading the distance between two adjacent lines
246 ($delta_x,$delta_y)= $img->stringBounds($string)
248 This method indicates the X and Y offsets (which may be negative)
249 that will occur when the given string is drawn using the current
250 font, fontsize and angle. When the string is drawn horizontally, it
251 gives the width and height of the string's bounding box.
252 $delta_x = $img->stringWidth($string)
254 This method indicates the width of the string given the current
255 font, fontsize and angle. It is the same as ($img->string‐
256 Bounds($string))[0]
257 ($x,$y) = $img->curPos
259 Return the current position of the pen. Set the current position
260 using moveTo().
261 $font = $img->font([$newfont] [,$newsize])
263 Get or set the current font. Fonts can be GD::Font objects, True‐
264 Type font file paths, or fontconfig font patterns like
265 "Times:italic" (see fontconfig). The latter feature requires that
266 you have the fontconfig library installed and are using libgd ver‐
267 sion 2.0.33 or higher.
268 As a shortcut, you may pass two arguments to set the font and the
270 fontsize simultaneously. The fontsize is only valid when drawing
271 with TrueType fonts.
272 $size = $img->fontsize([$newfontsize])
274 Get or set the current font size. This is only valid for TrueType
275 fonts.
276 $size = $img->penSize([$newpensize])
278 Get or set the current pen width for use during line drawing opera‐
279 tions.
280 $angle = $img->angle([$newangle])
282 Set the current angle for use when calling line() or move() with a
283 single argument.
284 Here is an example of using turn() and angle() together to draw an
286 octagon. The first line drawn is the downward-slanting top right
287 edge. The last line drawn is the horizontal top of the octagon.
288 $img->moveTo(200,50);
290 $img->angle(0);
291 $img->turn(360/8);
292 for (1..8) { $img->line(50) }
293 $angle = $img->turn([$newangle])
295 Get or set the current angle to turn prior to drawing lines. This
296 value is only used when calling line() or move() with a single
297 argument. The turning angle will be applied to each call to line()
298 or move() just before the actual drawing occurs.
299 Angles are in degrees. Positive values turn the angle clockwise.
301 $color = $img->fgcolor([$newcolor])
303 Get or set the pen's foreground color. The current pen color can
304 be set by (1) using an (r,g,b) triple; (2) using a previously-allo‐
305 cated color from the GD palette; or (3) by using a symbolic color
306 name such as "chartreuse." The list of color names can be obtained
307 using color_names().
308 $color = $img->bgcolor([$newcolor])
310 Get or set the pen's background color. The current pen color can
311 be set by (1) using an (r,g,b) triple; (2) using a previously-allo‐
312 cated color from the GD palette; or (3) by using a symbolic color
313 name such as "chartreuse." The list of color names can be obtained
314 using color_names().
315 $index = $img->translate_color(@args)
317 Translates a color into a GD palette or TrueColor index. You may
318 pass either an (r,g,b) triple or a symbolic color name. If you pass
319 a previously-allocated index, the method will return it unchanged.
320 $index = $img->alphaColor(@args,$alpha)
322 Creates an alpha color. You may pass either an (r,g,b) triple or a
323 symbolic color name, followed by an integer indicating its opacity.
324 The opacity value ranges from 0 (fully opaque) to 127 (fully trans‐
325 parent).
326 @names = GD::Simple->color_names
328 $translate_table = GD::Simple->color_names
329 Called in a list context, color_names() returns the list of sym‐
330 bolic color names recognized by this module. Called in a scalar
331 context, the method returns a hash reference in which the keys are
332 the color names and the values are array references containing
333 [r,g,b] triples.
334 $gd = $img->gd
336 Return the internal GD::Image object. Usually you will not need to
337 call this since all GD methods are automatically referred to this
338 object.
339 ($red,$green,$blue) = GD::Simple->HSVtoRGB($hue,$saturation,$value)
341 Convert a Hue/Saturation/Value (HSV) color into an RGB triple. The
342 hue, saturation and value are integers from 0 to 255.
343 ($hue,$saturation,$value) = GD::Simple->RGBtoHSV($hue,$satura‐
345 tion,$value)
346 Convert a Red/Green/Blue (RGB) value into a Hue/Saturation/Value
347 (HSV) triple. The hue, saturation and value are integers from 0 to
348 255.
349
351 This script will create an image showing all the symbolic colors.
352 #!/usr/bin/perl
354 use strict;
356 use GD::Simple;
357 my @color_names = GD::Simple->color_names;
359 my $cols = int(sqrt(@color_names));
360 my $rows = int(@color_names/$cols)+1;
361 my $cell_width = 100;
363 my $cell_height = 50;
364 my $legend_height = 16;
365 my $width = $cols * $cell_width;
366 my $height = $rows * $cell_height;
367 my $img = GD::Simple->new($width,$height);
369 $img->font(gdSmallFont);
370 for (my $c=0; $c<$cols; $c++) {
372 for (my $r=0; $r<$rows; $r++) {
373 my $color = $color_names[$c*$rows + $r] or next;
374 my @topleft = ($c*$cell_width,$r*$cell_height);
375 my @botright = ($topleft[0]+$cell_width,$topleft[1]+$cell_height-$legend_height);
376 $img->bgcolor($color);
377 $img->fgcolor($color);
378 $img->rectangle(@topleft,@botright);
379 $img->moveTo($topleft[0]+2,$botright[1]+$legend_height-2);
380 $img->fgcolor('black');
381 $img->string($color);
382 }
383 }
384 print $img->png;
386
388 The GD::Simple module is copyright 2004, Lincoln D. Stein. It is dis‐
389 tributed under the same terms as Perl itself. See the "Artistic
390 License" in the Perl source code distribution for licensing terms.
391 The latest versions of GD.pm are available at
393 http://stein.cshl.org/WWW/software/GD
395
397 GD, GD::Polyline, GD::SVG, Image::Magick
398perl v5.8.8 2006-08-23 GD::Simple(3)