Render Presentation Slides as SVG Images in PHP

What this page is about

Export PowerPoint slides as SVG images in PHP and control fonts, text, images, IDs, and events with Aspose.Slides.

Overview

SVG is a scalable XML-based image format that works well for web publishing, slide viewers, accessibility workflows, and automated post-processing. Aspose.Slides exports each slide to a separate SVG file and lets you control how text, fonts, pictures, and SVG elements are written.

Use SVGOptions when the exported SVG must be compact, predictable across browsers, or ready for interactive use.

Export a Slide as SVG

Create a Presentation, select a slide, and write it to a stream with Slide.writeAsSvg. The following example exports every slide in a presentation as a separate SVG file.

$presentation = new Presentation("presentation.pptx");
try {
    $slideCount = java_values($presentation->getSlides()->size());

    for ($slideIndex = 0; $slideIndex < $slideCount; $slideIndex++) {
        $slide = $presentation->getSlides()->get_Item($slideIndex);
        $slideNumber = java_values($slide->getSlideNumber());
        $outputFileName = sprintf("slide-%d.svg", $slideNumber);

        $svgStream = new Java("java.io.FileOutputStream", $outputFileName);
        $slide->writeAsSvg($svgStream);
        $svgStream->close();
    }
} finally {
    $presentation->dispose();
}

The filename uses Slide.getSlideNumber rather than the loop index. You can also export an individual shape with Shape.writeAsSvg when a slide viewer or web page needs only that shape.

Configure SVG Output

SVGOptions controls SVG rendering. For text frames, SVGOptions.setUseFrameSize includes the text frame in the rendering area, and SVGOptions.setUseFrameRotation determines whether the frame rotation is applied. Set SVGOptions.setDisableFontLigatures to true when text must be rendered without ligatures.

$presentation = new Presentation("presentation.pptx");
$svgStream = null;
try {
    $svgOptions = new SVGOptions();
    $svgOptions->setDisableFontLigatures(true);
    $svgOptions->setUseFrameSize(true);
    $svgOptions->setUseFrameRotation(false);

    $slide = $presentation->getSlides()->get_Item(0);
    $svgStream = new Java("java.io.FileOutputStream", "slide-with-custom-options.svg");
    $slide->writeAsSvg($svgStream, $svgOptions);
} finally {
    $svgStream->close();
    $presentation->dispose();
}

Control Text and Fonts

Vectorize All Text

Set SVGOptions.setVectorizeText to true to write all slide text as vector graphics. This eliminates font dependencies and makes the visual result more consistent across browsers, but the text is no longer selectable or searchable as SVG text.

$presentation = new Presentation("presentation.pptx");
$svgStream = null;
try {
    $svgOptions = new SVGOptions();
    $svgOptions->setVectorizeText(true);

    $slide = $presentation->getSlides()->get_Item(0);
    $svgStream = new Java("java.io.FileOutputStream", "slide-with-vectorized-text.svg");
    $slide->writeAsSvg($svgStream, $svgOptions);
} finally {
    $svgStream->close();
    $presentation->dispose();
}

Choose How External Fonts Are Handled

SVGOptions.setExternalFontsHandling uses a SvgExternalFontsHandling value for fonts that are loaded externally. Choose AddLinksToFontFiles to reference separate font files, Embed to include font data in the SVG, or Vectorize to render only text that uses external fonts as graphics. Verify font licensing before embedding fonts.

$presentation = new Presentation("presentation.pptx");
try {
    $slide = $presentation->getSlides()->get_Item(0);

    $linkedFontsOptions = new SVGOptions();
    $linkedFontsOptions->setExternalFontsHandling(SvgExternalFontsHandling::AddLinksToFontFiles);
    $linkedFontsStream = new Java("java.io.FileOutputStream", "slide-with-font-links.svg");
    try {
        $slide->writeAsSvg($linkedFontsStream, $linkedFontsOptions);
    } finally {
        $linkedFontsStream->close();
    }

    $embeddedFontsOptions = new SVGOptions();
    $embeddedFontsOptions->setExternalFontsHandling(SvgExternalFontsHandling::Embed);
    $embeddedFontsStream = new Java("java.io.FileOutputStream", "slide-with-embedded-fonts.svg");
    try {
        $slide->writeAsSvg($embeddedFontsStream, $embeddedFontsOptions);
    } finally {
        $embeddedFontsStream->close();
    }

    $vectorizedExternalFontsOptions = new SVGOptions();
    $vectorizedExternalFontsOptions->setExternalFontsHandling(SvgExternalFontsHandling::Vectorize);
    $vectorizedExternalFontsStream = new Java("java.io.FileOutputStream", "slide-with-vectorized-external-fonts.svg");
    try {
        $slide->writeAsSvg($vectorizedExternalFontsStream, $vectorizedExternalFontsOptions);
    } finally {
        $vectorizedExternalFontsStream->close();
    }
} finally {
    $presentation->dispose();
}

Reduce Embedded Image Size

Use SVGOptions.setPicturesCompression to reduce the resolution of embedded pictures, SVGOptions.setDeletePicturesCroppedAreas to omit cropped source areas, and SVGOptions.setJpegQuality to control JPEG encoding quality. These settings reduce file size at the cost of image fidelity or retained image data.

$presentation = new Presentation("presentation.pptx");
$svgStream = null;
try {
    $svgOptions = new SVGOptions();
    $svgOptions->setPicturesCompression(PicturesCompression::Dpi150);
    $svgOptions->setDeletePicturesCroppedAreas(true);
    $svgOptions->setJpegQuality(80);

    $slide = $presentation->getSlides()->get_Item(0);
    $svgStream = new Java("java.io.FileOutputStream", "compressed-slide.svg");
    $slide->writeAsSvg($svgStream, $svgOptions);
} finally {
    $svgStream->close();
    $presentation->dispose();
}

Assign Stable IDs to Shapes and Text

Provide a formatting callback to SVGOptions.setShapeFormattingController to set SvgShape.setId for each SVG shape. The callback can also set SvgTSpan.setId values on text tspan elements.

PhpJavaBridge cannot invoke a PHP callback from writeAsSvg when it runs in stream mode. Put the formatting logic in a small Java helper class, compile it, and add the resulting JAR file to the bridge classpath. The helper can use Shape.getOfficeInteropShapeId, which is stable for the lifetime of the shape, and a repeatable counter for its text spans. See the Java implementation of StableSvgIdController for the helper code.

After adding the compiled com.example.slides.StableSvgIdController class to the bridge classpath, instantiate it from PHP and assign it to SVGOptions:

$presentation = new Presentation("presentation.pptx");
$svgStream = null;
try {
    $shapeFormattingController = new Java("com.example.slides.StableSvgIdController");

    $svgOptions = new SVGOptions();
    $svgOptions->setShapeFormattingController($shapeFormattingController);

    $slide = $presentation->getSlides()->get_Item(0);
    $svgStream = new Java("java.io.FileOutputStream", "slide-with-stable-ids.svg");
    $slide->writeAsSvg($svgStream, $svgOptions);
} finally {
    $svgStream->close();
    $presentation->dispose();
}

Add SVG Event Handlers

In a formatting callback, call SvgShape.setEventHandler with a SvgEvent value to add a JavaScript event handler to an exported shape. Assign the callback with SVGOptions.setShapeFormattingController and define the JavaScript function in the page or SVG document that hosts the result.

As with stable IDs, implement the callback in a Java helper when PhpJavaBridge uses stream mode. The Java implementation of SvgEventController assigns an ID and an OnClick handler to a shape named ActionButton. Compile that helper, add it to the bridge classpath as com.example.slides.SvgEventController, and use it from PHP as follows:

$presentation = new Presentation("presentation.pptx");
$svgStream = null;
try {
    $shapeFormattingController = new Java("com.example.slides.SvgEventController");

    $svgOptions = new SVGOptions();
    $svgOptions->setShapeFormattingController($shapeFormattingController);

    $slide = $presentation->getSlides()->get_Item(0);
    $svgStream = new Java("java.io.FileOutputStream", "interactive-slide.svg");
    $slide->writeAsSvg($svgStream, $svgOptions);
} finally {
    $svgStream->close();
    $presentation->dispose();
}

The host page can define the JavaScript function referenced by the handler. Assigning IDs and event handlers enables slide viewers, accessibility enhancements, and other interactive SVG workflows.

FAQ

When should I use SVGOptions.setVectorizeText instead of SvgExternalFontsHandling.Vectorize?

Use SVGOptions.setVectorizeText when all text must be independent of fonts. Use SvgExternalFontsHandling.Vectorize when only text that uses external fonts should be converted to graphics.

What is the best way to make an SVG smaller?

Start by compressing embedded pictures, deleting cropped image areas, and choosing linked font files when the target environment can serve them. Test the result because lower image resolution, lower JPEG quality, and vectorized text each have different quality and size tradeoffs.

Can I modify exported SVG elements after export?

Yes. Assign IDs through a formatting callback, then select the matching SVG elements in your post-processing tool or browser script.