VSTGUI: COffscreenContext Class Reference

VSTGUI 4.10 Graphical User Interface Framework not only for VST plugins

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COffscreenContext Class Reference

A draw context using a bitmap as it's back buffer. More...

Inheritance diagram for COffscreenContext:

## Public Member Functions
CBitmap * | getBitmap () const
COffscreenContext Methods
void | copyFrom (CDrawContext *pContext, CRect destRect, CPoint srcOffset=CPoint(0, 0))
| copy from offscreen to pContext
CCoord | getWidth () const
CCoord | getHeight () const
Public Member Functions inherited from CDrawContext
virtual void | beginDraw ()
virtual void | endDraw ()
const CRect & | getSurfaceRect () const
virtual void | setBitmapInterpolationQuality (BitmapInterpolationQuality quality)
| set the current bitmap interpolation quality
const BitmapInterpolationQuality & | getBitmapInterpolationQuality () const
| get the current bitmap interpolation quality
virtual void | setLineStyle (const CLineStyle &style)
| set the current line style
const CLineStyle & | getLineStyle () const
| get the current line style
virtual void | setLineWidth (CCoord width)
| set the current line width
CCoord | getLineWidth () const
| get the current line width
virtual void | setDrawMode (CDrawMode mode)
| set the current draw mode, see CDrawMode
CDrawMode | getDrawMode () const
| get the current draw mode, see CDrawMode
virtual void | setClipRect (const CRect &clip)
| set the current clip
CRect & | getClipRect (CRect &clip) const
| get the current clip
virtual void | resetClipRect ()
| reset the clip to the default state
virtual void | setFillColor (const CColor &color)
| set current fill color
CColor | getFillColor () const
| get current fill color
virtual void | setFrameColor (const CColor &color)
| set current stroke color
CColor | getFrameColor () const
| get current stroke color
virtual void | setFontColor (const CColor &color)
| set current font color
CColor | getFontColor () const
| get current font color
virtual void | setFont (const CFontRef font, const CCoord &size=0, const int32_t &style=-1)
| set current font
const CFontRef | getFont () const
| get current font
CCoord | getStringWidth (UTF8StringPtr pStr)
| get the width of an UTF-8 encoded string
void | drawString (UTF8StringPtr string, const CRect &_rect, const CHoriTxtAlign hAlign=kCenterText, bool antialias=true)
| draw an UTF-8 encoded string
void | drawString (UTF8StringPtr string, const CPoint &_point, bool antialias=true)
| draw an UTF-8 encoded string
CCoord | getStringWidth (IPlatformString *pStr)
| get the width of a platform string
void | drawString (IPlatformString *string, const CRect &_rect, const CHoriTxtAlign hAlign=kCenterText, bool antialias=true)
| draw a platform string
void | drawString (IPlatformString *string, const CPoint &_point, bool antialias=true)
| draw a platform string
virtual void | setGlobalAlpha (float newAlpha)
| sets the global alpha value[0..1]
float | getGlobalAlpha () const
| get current global alpha value
virtual void | saveGlobalState ()
virtual void | restoreGlobalState ()
const CGraphicsTransform & | getCurrentTransform () const
const CRect & | getAbsoluteClipRect () const
virtual double | getScaleFactor () const
| returns the backend scale factor.
CCoord | getHairlineSize () const
| returns the current line size which corresponds to one pixel on screen.
void | drawLine (const CPoint &start, const CPoint &end)
virtual void | drawLine (const LinePair &line)=0
| draw a line
virtual void | drawLines (const LineList &lines)=0
| draw multiple lines at once
virtual void | drawPolygon (const PointList &polygonPointList, const CDrawStyle drawStyle=kDrawStroked)=0
| draw a polygon
virtual void | drawRect (const CRect &rect, const CDrawStyle drawStyle=kDrawStroked)=0
| draw a rect
virtual void | drawArc (const CRect &rect, const float startAngle1, const float endAngle2, const CDrawStyle drawStyle=kDrawStroked)=0
| draw an arc, angles are in degree
virtual void | drawEllipse (const CRect &rect, const CDrawStyle drawStyle=kDrawStroked)=0
| draw an ellipse
virtual void | drawPoint (const CPoint &point, const CColor &color)=0
| draw a point
virtual void | drawBitmap (CBitmap *bitmap, const CRect &dest, const CPoint &offset=CPoint(0, 0), float alpha=1.f)=0
| don't call directly, please use CBitmap::draw instead
virtual void | drawBitmapNinePartTiled (CBitmap *bitmap, const CRect &dest, const CNinePartTiledDescription &desc, float alpha=1.f)
virtual void | fillRectWithBitmap (CBitmap *bitmap, const CRect &srcRect, const CRect &dstRect, float alpha)
virtual void | clearRect (const CRect &rect)=0
| clears the rect (makes r = 0, g = 0, b = 0, a = 0)
virtual CGraphicsPath * | createGraphicsPath ()=0
| create a graphics path object, you need to forget it after usage
virtual CGraphicsPath * | createTextPath (const CFontRef font, UTF8StringPtr text)=0
| create a graphics path from a text
CGraphicsPath * | createRoundRectGraphicsPath (const CRect &size, CCoord radius)
| create a rect with round corners as graphics path, you need to forget it after usage
virtual void | drawGraphicsPath (CGraphicsPath *path, PathDrawMode mode=kPathFilled, CGraphicsTransform *transformation=nullptr)=0
virtual void | fillLinearGradient (CGraphicsPath *path, const CGradient &gradient, const CPoint &startPoint, const CPoint &endPoint, bool evenOdd=false, CGraphicsTransform *transformation=nullptr)=0
virtual void | fillRadialGradient (CGraphicsPath *path, const CGradient &gradient, const CPoint &center, CCoord radius, const CPoint &originOffset=CPoint(0, 0), bool evenOdd=false, CGraphicsTransform *transformation=nullptr)=0
Public Member Functions inherited from ReferenceCounted< T >
| ReferenceCounted ()=default
virtual | ~ReferenceCounted () noexcept=default
| ReferenceCounted (const ReferenceCounted &)
ReferenceCounted & | operator= (const ReferenceCounted &)
void | forget () override
| decrease refcount and delete object if refcount == 0
void | remember () override
| increase refcount
virtual int32_t | getNbReference () const
| get refcount

## Static Public Member Functions
static SharedPointer < COffscreenContext > | create (const CPoint &size, double scaleFactor=1.)
static SharedPointer < COffscreenContext > | create (CFrame *frame, CCoord width, CCoord height, double scaleFactor=1.)

## Protected Member Functions
| COffscreenContext (CBitmap *bitmap)
| COffscreenContext (const CRect &surfaceRect)
Protected Member Functions inherited from CDrawContext
| CDrawContext ()=delete
| CDrawContext (const CRect &surfaceRect)
| ~CDrawContext () noexceptoverride
virtual void | init ()
void | pushTransform (const CGraphicsTransform &transformation)
void | popTransform ()
const UTF8String & | getDrawString (UTF8StringPtr string)
void | clearDrawString ()
const CDrawContextState & | getCurrentState () const
CDrawContextState & | getCurrentState ()

## Protected Attributes
SharedPointer< CBitmap > | bitmap

## Additional Inherited Members
Public Types inherited from CDrawContext
using | LinePair = std::pair< CPoint, CPoint >
using | LineList = std::vector< LinePair >
using | PointList = std::vector< CPoint >
enum | PathDrawMode { kPathFilled, kPathFilledEvenOdd, kPathStroked }

## Detailed Description

A draw context using a bitmap as it's back buffer.

There are two usage scenarios :

# Drawing into a bitmap and then push the contents into another draw context

if (auto offscreen = COffscreenContext::create (frame, 100, 100))
{
offscreen->beginDraw ();
// ...
// draw into offscreen
// ...
offscreen->endDraw ();
offscreen->copyFrom (otherContext, destRect);
}

# Drawing static content into a bitmap and reuse the bitmap for drawing

if (cachedBitmap == 0)
{
if (auto offscreen = COffscreenContext::create (frame, 100, 100))
{
offscreen->beginDraw ();
// ...
// draw into offscreen
// ...
offscreen->endDraw ();
cachedBitmap = offscreen->getBitmap ();
if (cachedBitmap)
cachedBitmap->remember ();
}
}
if (cachedBitmap)
{
// ...
}

## Constructor & Destructor Documentation

COffscreenContext | ( | CBitmap * | bitmap | ) |
| explicitprotected

COffscreenContext | ( | const CRect & | surfaceRect | ) |
| explicitprotected

## Member Function Documentation

void copyFrom | ( | CDrawContext * | pContext,
|  | CRect | destRect,
|  | CPoint | srcOffset = `CPoint (0, 0)`
| ) |  |

copy from offscreen to pContext

SharedPointer< COffscreenContext > create | ( | const CPoint & | size,
|  | double | scaleFactor = `1.`
| ) |  |
| static

SharedPointer< COffscreenContext > create | ( | CFrame * | frame,
|  | CCoord | width,
|  | CCoord | height,
|  | double | scaleFactor = `1.`
| ) |  |
| static

CBitmap* getBitmap | ( |  | ) | const
| inline

CCoord getHeight | ( |  | ) | const

CCoord getWidth | ( |  | ) | const

## Member Data Documentation

SharedPointer<CBitmap> bitmap
| protected

The documentation for this class was generated from the following files:

- coffscreencontext.h
- coffscreencontext.cpp