OpenVG Specification
Version 1.1
Version 1.0 – August 1, 2005
Version 1.0.1 – January 26, 2007
Version 1.1 – December 3, 2008
Editors: Daniel Rice, Google, Inc.
Robert J. Simpson, AMD
“ ”
For Ilise – DSR
Copyright © 2005-2008 The Khronos Group Inc. All Rights Reserved.
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Table of Contents
1Introduction..................................................................................................................................10
1.1Feature Set..........................................................................................................................10
1.2Target Applications..............................................................................................................10
SVG and Adobe Flash Viewers .................................................................................................10
Portable Mapping Applications................................................................................................10
E-book Readers............................................................................................................................11
Games...........................................................................................................................................11
Scalable User Interfaces.............................................................................................................11
Low-Level Graphics Device Interface......................................................................................11
1.3Target Devices.....................................................................................................................11
1.4Design Philosophy...............................................................................................................11
1.5Naming and Typographical Conventions.............................................................................12
1.6Library Naming....................................................................................................................12
2The OpenVG Pipeline..................................................................................................................13
2.1Stage 1: Path, Transformation, Stroke, and Paint...............................................................14
2.2Stage 2: Stroked Path Generation.......................................................................................14
2.3Stage 3: Transformation......................................................................................................14
2.4Stage 4: Rasterization.........................................................................................................14
2.5Stage 5: Clipping and Masking............................................................................................15
2.6Stage 6: Paint Generation...................................................................................................15
2.7Stage 7: Image Interpolation...............................................................................................15
2.8Stage 8: Color Transformation, Blending, and Antialiasing..................................................16
2.9Multisampling......................................................................................................................16
3Constants, Functions and Data Types.........................................................................................16
3.1Versioning............................................................................................................................17
OPENVG_VERSION_1_1..........................................................................................................17
3.2Primitive Data Types............................................................................................................17
VGbyte..........................................................................................................................................17
VGubyte.......................................................................................................................................17
VGshort........................................................................................................................................17
VGint.............................................................................................................................................18
VGuint..........................................................................................................................................18
VGbitfield.....................................................................................................................................18
VGboolean...................................................................................................................................18
VGfloat.........................................................................................................................................18
3.3Floating-Point and Integer Representations........................................................................18
VG_MAXSHORT........................................................................................................................19
VG_MAXINT...............................................................................................................................19
VG_MAX_FLOAT.......................................................................................................................19
3.4Colors..................................................................................................................................19
3.4.1Linear and Non-Linear Color Representations............................................................20
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3.4.2Color Space Definitions...............................................................................................21
3.4.3Premultiplied Alpha......................................................................................................23
3.4.4Color Format Conversion............................................................................................23
3.5Enumerated Data Types......................................................................................................24
3.7Handle-based Data Types...................................................................................................25
VGHandle....................................................................................................................................25
VG_INVALID_HANDLE..........................................................................................................26
4The Drawing Context...................................................................................................................27
4.1Errors..................................................................................................................................29
VGErrorCode...............................................................................................................................29
vgGetError...................................................................................................................................30
4.2Manipulating the Context Using EGL ..................................................................................30
4.2.1EGLConfig Attributes...................................................................................................30
EGL_OPENVG_BIT....................................................................................................................30
EGL_ALPHA_MASK_SIZE.......................................................................................................31
4.2.2EGL Functions.............................................................................................................31
eglBindAPI...................................................................................................................................31
eglCreateContext.........................................................................................................................31
eglCreateWindowSurface..........................................................................................................31
eglCreatePbufferFromClientBuffer..........................................................................................32
eglMakeCurrent..........................................................................................................................32
eglGetCurrentContext................................................................................................................32
eglDestroyContext......................................................................................................................32
eglSwapBuffers............................................................................................................................32
4.3Forcing Drawing to Complete..............................................................................................33
vgFlush.........................................................................................................................................33
vgFinish........................................................................................................................................33
5Setting API Parameters...............................................................................................................34
5.1Context Parameter Types....................................................................................................34
VGParamType.............................................................................................................................34
5.2Setting and Querying Context Parameter Values................................................................36
vgSet..............................................................................................................................................36
vgGet and vgGetVectorSize .......................................................................................................37
5.2.1Default Context Parameter Values..............................................................................38
5.3Setting and Querying Object Parameter Values..................................................................40
vgSetParameter...........................................................................................................................40
vgGetParameter and vgGetParameterVectorSize ..................................................................41
6Rendering Quality and Antialiasing..............................................................................................44
6.1Rendering Quality................................................................................................................45
VGRenderingQuality.................................................................................................................45
6.2Additional Quality Settings...................................................................................................46
VGPixelLayout............................................................................................................................46
6.3Coordinate Systems and Transformations...........................................................................47
6.4Coordinate Systems............................................................................................................47
6.5Transformations...................................................................................................................48
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6.5.1Homogeneous Coordinates.........................................................................................48
6.5.2Affine Transformations.................................................................................................49
6.5.3Projective (Perspective) Transformations....................................................................49
6.6Matrix Manipulation.............................................................................................................50
VGMatrixMode...........................................................................................................................51
vgLoadIdentity............................................................................................................................51
vgLoadMatrix..............................................................................................................................51
vgGetMatrix.................................................................................................................................52
.......................................................................................................................................................52
vgMultMatrix..............................................................................................................................53
vgTranslate...................................................................................................................................53
vgScale..........................................................................................................................................54
vgShear.........................................................................................................................................54
vgRotate.......................................................................................................................................54
7Scissoring, Masking, and Clearing..............................................................................................55
7.1Scissoring............................................................................................................................55
VG_MAX_SCISSOR_RECTS.....................................................................................................55
Specifying Scissoring Rectangles..............................................................................................55
7.2Masking ..............................................................................................................................56
VGMaskOperation......................................................................................................................57
vgMask.........................................................................................................................................58
vgRenderToMask........................................................................................................................60
VGMaskLayer..............................................................................................................................61
vgCreateMaskLayer...................................................................................................................61
vgDestroyMaskLayer.................................................................................................................62
vgFillMaskLayer.........................................................................................................................62
vgCopyMask...............................................................................................................................63
7.3Fast Clearing.......................................................................................................................64
vgClear.........................................................................................................................................64
8Paths...........................................................................................................................................64
8.1Moves..................................................................................................................................65
8.2Straight Line Segments.......................................................................................................65
8.3Bézier Curves......................................................................................................................65
8.3.1Quadratic Bézier Curves.............................................................................................65
8.3.2Cubic Bézier Curves....................................................................................................66
8.3.3G1 Smooth Segments.................................................................................................66
8.3.4C1 Smooth Segments.................................................................................................67
8.3.5C2 Smooth Segments.................................................................................................68
8.3.6Converting Segments From Quadratic to Cubic Form.................................................68
8.4Elliptical Arcs.......................................................................................................................68
8.5The Standard Path Format..................................................................................................69
VG_PATH_FORMAT_STANDARD.........................................................................................70
8.5.1Path Segment Command Side Effects........................................................................70
8.5.2Segment Commands...................................................................................................71
8.5.3Coordinate Data Formats............................................................................................73
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