在 C++ 中将演示文稿幻灯片渲染为 SVG 图像
概述
SVG 是一种基于 XML 的可伸缩图像格式，适用于网页发布、幻灯片查看器、无障碍工作流和自动后处理。Aspose.Slides for C++ 将每张幻灯片导出为单独的 SVG 文件，并允许您控制文本、字体、图片和 SVG 元素的写入方式。
Use SVGOptions when the exported SVG must be compact, predictable across browsers, or ready for interactive use.
导出幻灯片为 SVG
Create a Presentation, select a slide, and write it to a stream. The following example exports every slide in a presentation as a separate SVG file.
#include <DOM/ISlide.h>
#include <DOM/Presentation.h>
#include <system/io/file.h>
#include <system/string.h>
using namespace Aspose::Slides;
using namespace System;
using namespace System::IO;
auto presentation = MakeObject<Presentation>(u"presentation.pptx");
auto slideCount = presentation->get_Slides()->get_Count();
for (int slideIndex = 0; slideIndex < slideCount; slideIndex++)
{
auto slide = presentation->get_Slide(slideIndex);
auto svgFileName = String::Format(u"slide-{0}.svg", slide->get_SlideNumber());
auto svgStream = File::Create(svgFileName);
slide->WriteAsSvg(svgStream);
svgStream->Dispose();
}
presentation->Dispose();
The filename uses ISlide::get_SlideNumber rather than the loop index. You can also export an individual shape with IShape::WriteAsSvg when a slide viewer or web page needs only that shape.
配置 SVG 输出
SVGOptions controls SVG rendering. For text frames, SVGOptions::set_UseFrameSize includes the text frame in the rendering area, and SVGOptions::set_UseFrameRotation determines whether the frame rotation is applied. Set SVGOptions::set_DisableFontLigatures to true when text must be rendered without ligatures.
#include <DOM/ISlide.h>
#include <DOM/Presentation.h>
#include <Export/SVGOptions.h>
#include <system/io/file.h>
using namespace Aspose::Slides;
using namespace Aspose::Slides::Export;
using namespace System;
using namespace System::IO;
auto presentation = MakeObject<Presentation>(u"presentation.pptx");
auto svgOptions = MakeObject<SVGOptions>();
svgOptions->set_DisableFontLigatures(true);
svgOptions->set_UseFrameSize(true);
svgOptions->set_UseFrameRotation(false);
auto slide = presentation->get_Slide(0);
auto svgStream = File::Create(u"slide-with-custom-options.svg");
slide->WriteAsSvg(svgStream, svgOptions);
svgStream->Dispose();
presentation->Dispose();
控制文本和字体
矢量化所有文本
Set SVGOptions::set_VectorizeText 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.
#include <DOM/ISlide.h>
#include <DOM/Presentation.h>
#include <Export/SVGOptions.h>
#include <system/io/file.h>
using namespace Aspose::Slides;
using namespace Aspose::Slides::Export;
using namespace System;
using namespace System::IO;
auto presentation = MakeObject<Presentation>(u"presentation.pptx");
auto svgOptions = MakeObject<SVGOptions>();
svgOptions->set_VectorizeText(true);
auto slide = presentation->get_Slide(0);
auto svgStream = File::Create(u"slide-with-vectorized-text.svg");
slide->WriteAsSvg(svgStream, svgOptions);
svgStream->Dispose();
presentation->Dispose();
选择外部字体的处理方式
SVGOptions::set_ExternalFontsHandling 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.
#include <DOM/ISlide.h>
#include <DOM/Presentation.h>
#include <Export/SVGOptions.h>
#include <Export/SvgExternalFontsHandling.h>
#include <system/io/file.h>
using namespace Aspose::Slides;
using namespace Aspose::Slides::Export;
using namespace System;
using namespace System::IO;
auto presentation = MakeObject<Presentation>(u"presentation.pptx");
auto slide = presentation->get_Slide(0);
auto linkedFontsOptions = MakeObject<SVGOptions>();
linkedFontsOptions->set_ExternalFontsHandling(SvgExternalFontsHandling::AddLinksToFontFiles);
auto linkedFontsStream = File::Create(u"slide-with-font-links.svg");
slide->WriteAsSvg(linkedFontsStream, linkedFontsOptions);
linkedFontsStream->Dispose();
auto embeddedFontsOptions = MakeObject<SVGOptions>();
embeddedFontsOptions->set_ExternalFontsHandling(SvgExternalFontsHandling::Embed);
auto embeddedFontsStream = File::Create(u"slide-with-embedded-fonts.svg");
slide->WriteAsSvg(embeddedFontsStream, embeddedFontsOptions);
embeddedFontsStream->Dispose();
auto vectorizedExternalFontsOptions = MakeObject<SVGOptions>();
vectorizedExternalFontsOptions->set_ExternalFontsHandling(SvgExternalFontsHandling::Vectorize);
auto vectorizedExternalFontsStream = File::Create(u"slide-with-vectorized-external-fonts.svg");
slide->WriteAsSvg(vectorizedExternalFontsStream, vectorizedExternalFontsOptions);
vectorizedExternalFontsStream->Dispose();
presentation->Dispose();
减小嵌入图像大小
Use SVGOptions::set_PicturesCompression to reduce the resolution of embedded pictures, SVGOptions::set_DeletePicturesCroppedAreas to omit cropped source areas, and SVGOptions::set_JpegQuality to control JPEG encoding quality. These settings reduce file size at the cost of image fidelity or retained image data.
#include <DOM/ISlide.h>
#include <DOM/Presentation.h>
#include <Export/PicturesCompression.h>
#include <Export/SVGOptions.h>
#include <system/io/file.h>
using namespace Aspose::Slides;
using namespace Aspose::Slides::Export;
using namespace System;
using namespace System::IO;
auto presentation = MakeObject<Presentation>(u"presentation.pptx");
auto svgOptions = MakeObject<SVGOptions>();
svgOptions->set_PicturesCompression(PicturesCompression::Dpi150);
svgOptions->set_DeletePicturesCroppedAreas(true);
svgOptions->set_JpegQuality(80);
auto slide = presentation->get_Slide(0);
auto svgStream = File::Create(u"compressed-slide.svg");
slide->WriteAsSvg(svgStream, svgOptions);
svgStream->Dispose();
presentation->Dispose();
为形状和文本分配稳定的 ID
Use ISvgShapeFormattingController to set ISvgShape::set_Id for each SVG shape. To set ISvgTSpan::set_Id values on text tspan elements as well, implement ISvgShapeAndTextFormattingController. Assign either controller with SVGOptions::set_ShapeFormattingController.
The following controller uses IShape::get_OfficeInteropShapeId, which is stable for the lifetime of the shape, and a repeatable counter for its text spans. This makes the generated IDs suitable for post-processing an unchanged presentation.
#include <DOM/IPortion.h>
#include <DOM/IShape.h>
#include <DOM/ISlide.h>
#include <DOM/ITextFrame.h>
#include <DOM/Presentation.h>
#include <Export/ISvgShape.h>
#include <Export/ISvgShapeAndTextFormattingController.h>
#include <Export/ISvgTSpan.h>
#include <Export/SVGOptions.h>
#include <system/io/file.h>
#include <system/string.h>
using namespace Aspose::Slides;
using namespace Aspose::Slides::Export;
using namespace System;
using namespace System::IO;
class StableSvgIdController : public ISvgShapeAndTextFormattingController
{
private:
String m_currentShapeId;
int m_textSpanIndex = 0;
public:
void FormatShape(SharedPtr<ISvgShape> svgShape, SharedPtr<IShape> shape) override
{
m_currentShapeId = String::Format(u"shape-{0}", shape->get_OfficeInteropShapeId());
m_textSpanIndex = 0;
svgShape->set_Id(m_currentShapeId);
}
void FormatText(SharedPtr<ISvgTSpan> svgTSpan, SharedPtr<IPortion> portion,
SharedPtr<ITextFrame> textFrame) override
{
auto currentTextSpanIndex = m_textSpanIndex;
m_textSpanIndex++;
svgTSpan->set_Id(String::Format(u"{0}-text-{1}", m_currentShapeId, currentTextSpanIndex));
}
};
auto presentation = MakeObject<Presentation>(u"presentation.pptx");
auto svgOptions = MakeObject<SVGOptions>();
svgOptions->set_ShapeFormattingController(MakeObject<StableSvgIdController>());
auto slide = presentation->get_Slide(0);
auto svgStream = File::Create(u"slide-with-stable-ids.svg");
slide->WriteAsSvg(svgStream, svgOptions);
svgStream->Dispose();
presentation->Dispose();
添加 SVG 事件处理程序
In an ISvgShapeFormattingController, call ISvgShape::SetEventHandler with a SvgEvent value to add a JavaScript event handler to an exported shape. Assign the controller with SVGOptions::set_ShapeFormattingController and define the JavaScript function in the page or SVG document that hosts the result.
#include <DOM/IShape.h>
#include <DOM/ISlide.h>
#include <DOM/Presentation.h>
#include <Export/ISvgShape.h>
#include <Export/ISvgShapeFormattingController.h>
#include <Export/SVGOptions.h>
#include <Export/SvgEvent.h>
#include <system/io/file.h>
using namespace Aspose::Slides;
using namespace Aspose::Slides::Export;
using namespace System;
using namespace System::IO;
class SvgEventController : public ISvgShapeFormattingController
{
public:
void FormatShape(SharedPtr<ISvgShape> svgShape, SharedPtr<IShape> shape) override
{
if (shape->get_Name() == u"ActionButton")
{
svgShape->set_Id(u"action-button");
svgShape->SetEventHandler(SvgEvent::OnClick, u"handleShapeClick(event)");
}
}
};
auto presentation = MakeObject<Presentation>(u"presentation.pptx");
auto svgOptions = MakeObject<SVGOptions>();
svgOptions->set_ShapeFormattingController(MakeObject<SvgEventController>());
auto slide = presentation->get_Slide(0);
auto svgStream = File::Create(u"interactive-slide.svg");
slide->WriteAsSvg(svgStream, svgOptions);
svgStream->Dispose();
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.
常见问题
何时应该使用 SVGOptions::set_VectorizeText 而不是 SvgExternalFontsHandling::Vectorize？
Use SVGOptions::set_VectorizeText when all text must be independent of fonts. Use SvgExternalFontsHandling::Vectorize when only text that uses external fonts should be converted to graphics.
怎样才能让 SVG 更小？
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.
导出后我可以修改 SVG 元素吗？
Yes. Assign IDs through a formatting controller, then select the matching SVG elements in your post-processing tool or browser script.