TQRHotPDFExportFilter

QuickReport adapter (Lib\Addons\QuickReport\qrHotPDFExport.pas)

QuickReport export filter，使用 HotPDF 作為底層 PDF backend，而不是 QuickReport 自己的 QRPDFFilter。適用於已嵌入 HotPDF，並希望整個應用程式共用單一 PDF backend 的專案QRPDFFilter. Intended for projects that already embed HotPDF and want a single PDF backend across the whole application.

  TQRHotPDFExportFilter = class(TQRExportFilter)

  public

    constructor Create(Filename: string); override;

    procedure SetOutputStream(AStream: TStream);

    property Title, Author, Subject, Keywords: string;

    property PDFVersion: TPDFVersType;

    property Compressed: Boolean;

    property CompressionLevel: TPDFCompressionLevel;

  end;

說明

TQRHotPDFExportFilter 繼承自 TQRExportFilter，因此不需修改 QuickReport core，即可接入一般 MyReport.ExportToFilter(MyExporterInstance) workflow。由於 TQRExportFilter 不是 TComponent descendant（在 QuickReport 設計中是 plain class），因此沒有 IDE component registration；呼叫端需直接透過 Create('out.pdf') 建立 TQRHotPDFExportFilter

QuickReport 會將每個已準備頁面 render 成快取於 QRPrinter.PageList 的 TMetafile。adapter 不重新實作完整 per-component TextOut / AcceptGraphic / AcceptBand callback set，而是忽略它們（no-op overrides），並在 Finish 中收集各頁 metafiles：

1. Start(PaperWidth, PaperHeight, Font) - 建立 THotPDF instance、設定 metadata、呼叫 BeginDoc，並儲存 (PaperWidth, PaperHeight)，讓 Finish 可正確 shaping pages

2. NewPage / EndPage / TextOut / AcceptGraphic - no-op (the metafile already has the rendered content).TQRHotPDFExportFilter directly via Create('out.pdf').

QuickReport renders each prepared page into a TMetafile cached in QRPrinter.PageList. Rather than re-implementing the entire per-component TextOut / AcceptGraphic / AcceptBand callback set, the adapter ignores those (no-op overrides) and harvests the per-page metafiles in Finish:

1. Start(PaperWidth, PaperHeight, Font) - create the THotPDF instance, set metadata, call BeginDoc, and save (PaperWidth, PaperHeight) so Finish can shape pages correctly.

2. NewPage / EndPage / TextOut / AcceptGraphic - no-op (the metafile already has the rendered content).

3. Finish - for each cached QRPrinter.PageList[i] metafile, add (or reuse) a HotPDF page sized to PaperWidth / PaperHeight in points and call ShowEnhancedMetafile. Then EndDoc and release.

3. Finish - 對每個快取的 QRPrinter.PageList[i] metafile，加入（或重用）尺寸為 PaperWidth / PaperHeight points 的 HotPDF page，並呼叫 ShowEnhancedMetafile。接著 EndDoc 並釋放

屬性Title / Author / Subject / Keywords - document metadata. When Title is empty the adapter falls back to Filename so the PDF always has a non-empty title. Set before ExportToFilter is called.

Title / Author / Subject / Keywords - 檔案 metadata。Title 為空時，adapter 會 fallback 到 Filename，因此 PDF 一定有非空 title。請在呼叫 ExportToFilter 前設定PDFVersion - PDF specification level the document should target. Defaults to pdf17.

PDFVersion - PDF specification level the document should target. Defaults to pdf17.

Compressed - HotPDF stream compression on (default True). Set False for diagnostic PDFs.

CompressionLevel - FlateDecode level. Defaults to clDefault.

SetOutputStream(AStream) - route the PDF bytes into AStream instead of writing to disk. Call before ExportToFilter. Internally a temp file is used because HotPDF saves on CompressionLevel - FlateDecode level. Defaults to clDefault.

SetOutputStream(AStream) - 將 PDF bytes 導入 AStream，而不是寫入磁碟。請在 ExportToFilter 前呼叫。內部會使用暫存檔，因為 HotPDF 在 EndDoc 時儲存；bytes 會在 Finish 中串流回去

Typical workflow

Filter := TQRHotPDFExportFilter.Create('Report.pdf');

try

  Filter.Title := 'Monthly Statement';

  Filter.PDFVersion := pdf17;

  QuickRep1.ExportToFilter(Filter);

finally

  Filter.Free;

end;

Capabilities preserved

Vector and raster page content rendered by QuickReport's standard preview / printer pipeline. GDI-resolved text strings. Page sizing follows the PaperWidth / PaperHeight handed to Start by QuickReport.

Limitations of the metafile bridge

由於頁面會擷取為 enhanced metafiles，需要結構資訊的 QuickReport-specific PDF features（AcroForm fields、named destinations、outlines、PDF/A 或 PDF/X conformance gates）不會傳遞。輸出會忠實重現 QuickReport render 的視覺結果，但不是 structured PDF

Packaging note

adapter 位於 Lib\Addons\QuickReport\，且不屬於主要 HotPDF*.dpk packages，因此 QuickReport dependency 只會由選用此 adapter 的專案拉入。smoke test（smoke_qr_hotpdf.dpr）與該 unit 放在同一處Lib\Addons\QuickReport\ and is not part of the main HotPDF*.dpk packages, so the QuickReport dependency is only pulled in by projects that opt in to the adapter. A smoke test (smoke_qr_hotpdf.dpr) lives alongside the unit.

請參閱： TfrxHotPDFExport, TppHotPDFDevice, dxHotPDFExportReportLink, THPDFPage.ShowMetafile, Enhanced EMF/WMF Support