Встраивайте workflow PDFium VCL Component в приложения Delphi и C++Builder или workflow PDFium LCL Component в Lazarus/FPC, используя компоненты с исходным кодом для просмотра, рендеринга, форм, печати, preflight-отчетов и проверки по стандартам.
Эта статья предназначена для teams sharing PDF viewing code between Delphi, Lazarus, and Free Pascal applications. Она рассматривает Lazarus and Free Pascal viewer integration как промышленную инженерию документов, а не как одиночный вызов компонента.
Практический риск состоит в том, что a viewer can compile in multiple IDEs yet fail in deployment because widget-set behavior, binary loading, calling conventions, and resource paths differ. Поэтому процессу нужны письменный контракт, наблюдаемая диагностика и реалистичные регрессионные файлы.
Архитектурные решения
Treat the viewer layer as portable infrastructure. supported IDEs, compiler versions, CPU architectures, and widget sets / PDFium binary location, bitness, load failure message, and update policy
- supported IDEs, compiler versions, CPU architectures, and widget sets
- PDFium binary location, bitness, load failure message, and update policy
- high-DPI scaling, mouse wheel, keyboard, and focus behavior across frameworks
- feature parity expectations for thumbnails, search, forms, printing, and annotations
Порядок реализации
Stabilize runtime loading before adding UI features. The order below keeps the workflow reviewable for Delphi and C++Builder teams.
- create a small viewer shell that loads the PDFium runtime before opening documents
- normalize paths and binary names for each supported deployment layout
- exercise zoom, scroll, selection, and focus events on every widget set
- separate shared PDF logic from framework-specific panels and dialogs
- package diagnostics that identify missing binaries and architecture mismatches
Доказательства проверки
Deployment evidence for mixed-toolchain support. Keep these fields with the output or support record.
- compiler, widget set, target architecture, PDFium binary path, and runtime version
- load success or failure reason before the first document is opened
- input-event test results for wheel, drag, keyboard, focus, and high-DPI scaling
- feature matrix showing which viewer actions are supported in each build
Portability is a packaging decision
A Lazarus and FPC integration should define how the PDFium binary is found, which widget sets are supported, how DPI and input events are normalized, and which viewer features are guaranteed across platforms.
Operational metrics to watch
The first release should expose enough metrics to prove the workflow is healthy under real files, not only under curated samples.
- count and rate for compiler, widget set, target architecture, PDFium binary path, and runtime version
- warning trend for a 32-bit application cannot load a 64-bit PDFium binary
- latency of the stage that must create a small viewer shell that loads the PDFium runtime before opening documents
- profile usage for supported IDEs, compiler versions, CPU architectures, and widget sets
Engineering review notes for Lazarus and Free Pascal viewer integration
Use these review notes to make sure the feature has moved beyond a demo and can be defended during release, support, and customer escalation.
- Decision: supported IDEs, compiler versions, CPU architectures, and widget sets. Implementation pressure point: normalize paths and binary names for each supported deployment layout. Acceptance evidence: input-event test results for wheel, drag, keyboard, focus, and high-DPI scaling. Regression trigger: printing and file dialogs may need framework-specific wrappers
- Decision: PDFium binary location, bitness, load failure message, and update policy. Implementation pressure point: exercise zoom, scroll, selection, and focus events on every widget set. Acceptance evidence: feature matrix showing which viewer actions are supported in each build. Regression trigger: a 32-bit application cannot load a 64-bit PDFium binary
- Decision: high-DPI scaling, mouse wheel, keyboard, and focus behavior across frameworks. Implementation pressure point: separate shared PDF logic from framework-specific panels and dialogs. Acceptance evidence: compiler, widget set, target architecture, PDFium binary path, and runtime version. Regression trigger: relative paths often work in the IDE and fail from installed shortcuts
Пограничные случаи
- a 32-bit application cannot load a 64-bit PDFium binary
- relative paths often work in the IDE and fail from installed shortcuts
- widget-set differences can alter focus behavior in docked panes
- printing and file dialogs may need framework-specific wrappers
Delphi / C++Builder notes
PDFium Component should sit behind a small service boundary that receives files, streams, profiles, and credentials, then returns output paths, warnings, metrics, and validation status. Important terms include Lazarus, Free Pascal, LCL, PDFium, widget set, runtime loading.
Пример кода Delphi
Следующий эскиз Delphi показывает практическую границу сервиса для этой темы. Оставляйте проверки политики, журналирование и валидацию вне узкого блока вызова продукта, чтобы сценарий было проще тестировать.
procedure TMainForm.OpenDocument(const FileName: string);
begin
PdfView.LoadFromFile(FileName);
TrackDocumentLifetime(FileName, PdfView.PageCount);
PageSpinEdit.MaxValue := PdfView.PageCount;
RenderCurrentPage;
UpdateToolbarState;
end;Производственный чек-лист
- Run the workflow on an empty file, a normal customer file, and a worst-case file
- Open the generated PDF with the target viewer, validator, printer, or downstream application
- Log product version, profile version, input hash, output path, elapsed time, and warning count
- Keep passwords, certificates, temporary files, and customer data under explicit retention rules
- Add regression documents when a customer file exposes a new edge case