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Place Images in an XPS OM

Describes how to place images in an XPS OM.

To place images in an XPS OM, create a path object that defines the location and outline of an image, then use an image brush to fill the path. Add the created path object to the page's or canvas' list of visual objects, so that it can be rendered with the other visual content.

Before using these code examples in your program, read the disclaimer in Common XPS Document Programming Tasks.

Code Example

Create image resource

If the source image is not available in the XPS OM as an image resource, first create the image resource:


    HRESULT                hr = S_OK;
    IStreamPtr             imageStream; // the resulting image stream
    IOpcPartUri            *imagePartUri;
    IXpsOMImageResource    *imageResource;

     XPS_RECT    rect = {0.0f, 0.0f, 0.0f, 0.0f}; // set to image size

    hr = xpsFactory->CreateReadOnlyStreamOnFile ( 
            imageFileName, &imageStream );

    hr = xpsFactory->CreatePartUri( imagePartName, &imagePartUri );

    imageType; // set to type of image being read in
    hr = xpsFactory->CreateImageResource ( 
        imageStream,
        imageType,
        imagePartUri,
        &imageResource);
    imagePartUri->Release();
    imageStream->Release();

    // imageResource can now be used by other parts in the XPS OM.


Place image into visual collection

If the source image is available in the XPS OM as an image resource, it can be used to create an image brush object and added as the fill brush to the path that describes the image location and size in the page.


    // These variables are initialized outside of this code example,
    //  for example, as the parameters of a method or from some 
    //  preceding program code.

    // dimensions of the image in pixels
    XPS_SIZE    bmpDim = {0,0} ; 

    // DPI resolution values obtained from image
    FLOAT        dpiX = 96.0f;
    FLOAT        dpiY = 96.0f;
    
    // initialize viewport values 
    XPS_RECT    viewPort = {0.0,0.0,0.0,0.0};

    // initialize viewbox values
    XPS_RECT    viewBox = {0.0,0.0,0.0,0.0}; 

    // These are part of this code example.
    IXpsOMPath *imageRectPath;
    IXpsOMImageBrush *imageBrush;
    IXpsOMVisualCollection *pageVisuals;

    // Describe image source dimensions and set viewbox to be the 
    // entire image DIP width of image. 
    //  Example: 
    //    600 image pixels, 300 dpi -> 2 inches -> 2 * 96 = 192 DIP width
    viewBox.width = FLOAT((double)bmpDim.width * 96.0 / dpiX); 
    viewBox.height = FLOAT((double)bmpDim.height * 96.0 / dpiY);

    // Describe the size and position of the image destination.
    //  rect is an XPS_RECT structure that is initialized outside
    //  of this sample for example, it might be passed in as a parameter.

    // destination rectangle
    viewPort.x = rect.x;
    viewPort.y = rect.y;
    viewPort.width = rect.width;
    viewPort.height = rect.height;

    // Create the image brush.
    hr = xpsFactory->CreateImageBrush(imageResource, &viewBox, &viewPort, 
        reinterpret_cast<IXpsOMImageBrush**>(&imageBrush));

    // Create the path that describes the outline of the image on the page.
    //  This step uses the function described in the next code example.
    hr = CreateRectanglePath(xpsFactory, &rect,
        reinterpret_cast<IXpsOMPath**>(&imageRectPath));

    // Set the accessibility description for the path object as required.
    hr = imageRectPath->SetAccessibilityShortDescription( shortDescText );

    // Set the image brush to be the fill brush for this path.
    hr = imageRectPath->SetFillBrushLocal( imageBrush );

    // Get the list of visuals for this page...
    hr = xpsPage->GetVisuals( &pageVisuals );

    // ...and add the completed path to the list.
    hr = pageVisuals->Append( imageRectPath );

    // Release locally created interfaces.
    if (NULL != pageVisuals) pageVisuals->Release();
    if (NULL != imageRectPath) imageRectPath->Release();
    if (NULL != imageBrush) imageBrush->Release();



Create path object for image

The following method accepts an XPS_RECT structure and creates a rectangular path.


HRESULT 
CreateRectanglePath(
    __in  IXpsOMObjectFactory   *xpsFactory,
    __in  const XPS_RECT        *rect,
    __out IXpsOMPath            **rectPath
)
{
   
    HRESULT hr = S_OK;

    IXpsOMGeometryFigure           *rectFigure;
    IXpsOMGeometry                 *imageRectGeometry;
    IXpsOMGeometryFigureCollection *geomFigureCollection;

    // Define start point and three of the four sides of the rectangle.
    //  The fourth side is implied by setting the path type to CLOSED.
    XPS_POINT            startPoint = {rect->x, rect->y};
    XPS_SEGMENT_TYPE     segmentTypes[3] = {
        XPS_SEGMENT_TYPE_LINE, 
        XPS_SEGMENT_TYPE_LINE, 
        XPS_SEGMENT_TYPE_LINE
    };
    FLOAT segmentData[6] = {
        rect->x,              rect->y+rect->height, 
        rect->x+rect->width,  rect->y+rect->height, 
        rect->x+rect->width,  rect->y 
    };
    BOOL segmentStrokes[3] = {
        TRUE, TRUE, TRUE
    };

    // Create a closed geometry figure using the three 
    //  segments defined above.

    hr = xpsFactory->CreateGeometryFigure( &startPoint, &rectFigure );
    hr = rectFigure->SetIsClosed( TRUE );
    hr = rectFigure->SetIsFilled( TRUE );
    hr = rectFigure->SetSegments( 3, 6, 
            segmentTypes, segmentData, segmentStrokes );

    // Create a geometry that consists of the figure created above.
    hr = xpsFactory->CreateGeometry( &imageRectGeometry );
    hr = imageRectGeometry->GetFigures( &geomFigureCollection );
    hr = geomFigureCollection->Append( rectFigure );

    // Create the path that consists of the geometry created above
    //  and return the pointer in the parameter passed in to the function.
    hr = xpsFactory->CreatePath( reinterpret_cast<IXpsOMPath**>(rectPath) );
    hr = (*rectPath)->SetGeometryLocal( imageRectGeometry );

    // The calling method will release these interfaces when 
    //  it is done with them.

    return hr;
}


Related topics

Next Steps
Navigate the XPS OM
Write Text to an XPS OM
Draw Graphics in an XPS OM
Write an XPS OM to an XPS Document
Print an XPS OM
Used in This Page
IOpcPartUri
IXpsOMImageBrush
IXpsOMImageResource
IXpsOMGeometry
IXpsOMGeometryFigure
IXpsOMGeometryFigureCollection
IXpsOMObjectFactory
IXpsOMPackage
IXpsOMPath
IXpsOMVisualCollection
For More Information
Initialize an XPS OM
XPS Document API Reference
XML Paper Specification

 

 

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