Table of Contents

Part 1 Foundations 1

1 Overview of graphics 3

1.1 Perl and graphics 4

1.2 The bits and pieces in graphics programming 5

1.3 Color spaces and palettes 7

RGB 7 . CMY and CMYK 8 . HSV and HLS 9

YUV, YIQ and YCbCr 12 . Grayscale 12

Color distance 13 . Reducing the number of colors in an image 13

1.4 Summary 14

2 Overview of graphics file formats 15

2.1 Some graphics formats 16

GIF 17 . JPEG, JFIF 18 . PNG 18

MNG 19 . SVG 19 . TIFF 19

2.2 Finding the size and type of an image 20

Image::Size 20 . Image::Magick 21

Do it yourself 22 . More on file size and information 24

2.3 Conversion of graphics formats 24

2.4 Summary 26

3 Overview of tools and modules 27

3.1 CPAN 28

3.2 The tools 29

The Chart::* modules 29 . Gnuplot 29

GD 29 . GD::Graph, GIFgraph and Chart::PNGgraph 30

GD::Text 30 . The Gimp 30 . Image::Magick 30

Image::Size 31 . Inline 31 . OpenGL 32

PGPLOT 32 . RenderMan 33 . Term::Gnuplot 33

3.3 A note on module versions 34

3.4 Summary 34

Part 2 Creating graphics 35

4 Drawing 37

4.1 Drawing with GD 39

An example drawing 40 . Filling objects 42

Drawing text with GD 43 . GD.s built-in fonts 44

TrueType fonts and GD 45

4.2 Drawing with Image::Magick 46

An example drawing 46 . Anti-alias and fuzz 47

Drawing by combining images 48 . Drawing with paths 50

Drawing text with Image::Magick 51

4.3 Combining GD and Image::Magick 53

4.4 Drawing with Term::Gnuplot 55

4.5 PostScript and SVG 59

4.6 Summary 59

5 Creating charts 60

5.1 GD::Graph and friends 62

Preparing your data sets for GD::Graph 63

Controlling the look of your chart 65

GD::Graph and fonts 65 . Saving your chart to a file 66

Bar and area charts 68 . Lines, Points and LinesPoints charts 70 . Mixed charts 72

5.2 The Chart distribution 74

Pareto charts 75

5.3 PGPLOT 76

PGPLOT devices 76 . Example: A simple X-Y plot 77

Example: A contour plot 81 . Example: Plotting a galaxy 84

5.4 Interfacing with gnuplot 85

5.5 Summary 89

6 Graphics and the Web 90

6.1 The Common Gateway Interface 91

HTTP and CGI 91

6.2 Suitable image formats 92

Web safe color palettes 92

6.3 CGI and dynamically generated graphics 94

6.4 Forms and encapsulated graphics 96

6.5 Image collections and thumbnailing 100

Thumbnails with Image::Magick 101

Thumbnails with GD 102 . Contact sheets with Image::Magick.s . visual directory 103

Contact sheets with Image::Magick::Montage 104

An example application: A web photo album 105

Designing the data 107

6.6 Summary 121

7 Animations for the Web 122

7.1 Animation file formats 123

GIF 123 . MNG 124

Macromedia Flash 124 . SVG 125

7.2 GIF animations 125

7.3 Perl and animations 126

7.4 Repeatedly applying a filter 127

Example: making objects appear 127

Example: Zooming in on an object 129

7.5 Animated text 131

7.6 Animated charts 132

7.7 Animations with the Gimp 134

7.8 Summary 137

8 Resizing and combining images 138

8.1 Scaling and cropping an image 139

Image::Magick geometry specification 139

Cropping an image 140

8.2 Combining Images 140

Combining GD images 140

Combining Image::Magick images 142

Adding a watermark to an image 145

8.3 Summary 151

9 Three-dimensional graphics 153

9.1 OpenGL 154

OpenGL library functions in Perl 155

Capturing your OpenGL output 157

Example: a planetary system 160

OpenGL summary 164

9.2 RenderMan 164

How to use the module and the BMRT 165

The RenderMan language binding for Perl 166

Example: A rotating cube of cubes 167

9.3 Summary 172

Part 3 Special topics 173

10 Writing your own graphics modules 175

10.1 Interface design 176

Coordinate transformation 180

Choosing your drawing primitives 181

Implementing the interface 182

10.2 An OO implementation of a clock 186

10.3 Summary 188

11 Controlling text placement 190

11.1 Determining text size 191

Text sizes in GD 191

Text sizes in Image::Magick 192

11.2 Aligning text in graphics 194

Aligning text with GD 194

Aligning text with Image::Magick 196

11.3 Wrapping text 197

The GD::Text modules 207

11.4 Summary 209

12 Manipulating pixels and transparency 210

12.1 GD and pixels 211

Example: rotating RGB values 211

Removing duplicate color palette entries 212

12.2 Image::Magick and pixels 213

Rotating RGB values 214

12.3 Convolution 215

Convolution with Image::Magick 217

Using Image::Magick's Convolve() method 224

Convolution with PDL 226

12.4 Alpha channels and transparency 229

Transparency and the GD module 229

Transparency and Image::Magick 230

How to view partially transparent images 233

12.5 Fast manipulation of image pixels 233

Using Inline::C 234

12.6 Summary 238

Part 4 Appendices 239

A Image::Magick introduction & reference 241

B Color space conversion algorithms 284

C Module code 288

 
references 293
index 295