Functional Cross-Reference in PDF (Page 2 of 2)

Problem is on server return -> 413 Request Entity Too Large

So put your code to github, and create tag after you can import big files under the tag, I don't know the limit size?

Please put your code on Github if you can, for us it's more esay to see which code changes!

It is very easy if you have git, ssh, etc on your setup, but I remenber you use macOS, so no problem!

On Terminal get your github repository

git clone https://github.com/Kellermorph/QuerverweiseAppImage.git

Now work in QuerverweiseAppImage folder with your IDE as usual,
but if you want use terminal:

for adding files or files changed use

git add  file_name  

git diff

what files was added or removed.

- it is removed
+ it is added

For upload your changes to your online Github branch, it's very easy.

git push

For refreshing your local repository.

git pull

Same for me ....,
in first you talk avout QET 's code, now I see a python file, it 's me or then I need to return to bed for rest?

Maybe it's also due to my poor English. I apologize for that.
I had first tried the source code via chatgpt. That was not successful. PLC-User then asked me to compile the code myself and give it a try. But in my current situation this is too complicated / time-consuming. That's why I've been looking for an alternative that can at least temporarily help me and possibly some others. I have written a small Python program (with the help of ChatGPT), which searches a finished exported circuit diagram (PDF) for cross-references and then links them. However, only to the page and not directly to the component.

Translated with DeepL.com (free version)

@plc-user,
I was able to fix my error...I re-imported the attached files from the rsnapthot backup and on the server for SQL database with phpMyAdmin I re imported the old ‘punbb_attach_files’ table for recreate these ‘indexes!

But the last backup was made yesterday at 15h00, so please put again your script, many sorry.

In the meantime, I have written a code that creates a position list with links and targets in the print module that can be used to insert PDF links.
I just haven't found anything in the Qt docs that explains what a link or a corresponding target should look like so that it works in the PDF file!

***** find positions for PDF-internal links...
XRef from page 3 QPoint(1380,620) to page 4 QPoint(120,440)
XRef from page 3 QPoint(1380,770) to page 4 QPoint(120,90)
XRef from page 3 QPoint(1380,640) to page 4 QPoint(120,420)
XRef from page 3 QPoint(1380,600) to page 4 QPoint(120,400)
XRef from page 3 QPoint(1380,790) to page 4 QPoint(120,110)
XRef from page 4 QPoint(120,90) to page 3 QPoint(1380,770)
XRef from page 4 QPoint(1320,90) to page 5 QPoint(120,90)
XRef from page 4 QPoint(120,110) to page 3 QPoint(1380,790)
XRef from page 4 QPoint(120,440) to page 3 QPoint(1380,620)
XRef from page 4 QPoint(1320,110) to page 5 QPoint(120,110)
XRef from page 4 QPoint(120,400) to page 3 QPoint(1380,600)
XRef from page 4 QPoint(120,420) to page 3 QPoint(1380,640)
XRef from page 5 QPoint(1380,90) to page 6 QPoint(120,90)
XRef from page 5 QPoint(120,90) to page 4 QPoint(1320,90)
XRef from page 5 QPoint(1380,110) to page 6 QPoint(120,110)
XRef from page 5 QPoint(120,110) to page 4 QPoint(1320,110)
XRef from page 6 QPoint(120,110) to page 5 QPoint(1380,110)
XRef from page 6 QPoint(1380,270) to page 8 QPoint(110,180)
XRef from page 6 QPoint(1380,440) to page 8 QPoint(110,440)
XRef from page 6 QPoint(1380,410) to page 8 QPoint(110,410)
XRef from page 6 QPoint(1380,240) to page 8 QPoint(110,210)
XRef from page 6 QPoint(120,90) to page 5 QPoint(1380,90)
XRef from page 8 QPoint(110,440) to page 6 QPoint(1380,440)
XRef from page 8 QPoint(110,180) to page 6 QPoint(1380,270)
XRef from page 8 QPoint(110,410) to page 6 QPoint(1380,410)
XRef from page 8 QPoint(110,210) to page 6 QPoint(1380,240)

There are also additional constraints such as fitting on the page or the print area. "Automagic" zoom factors are used here, which also have to be applied to the positions of the links and targets.

Based on the qt6-make branch with some more cleanup regarding Qt version checks.

By the way: I have to take a closer look at git-branches. How to use them and so ... 

Ich bin seit langem mit ChatGPT dran, und versuche die Verlinkung hinzubekommen.

Wir arbeiten auf dem Skript von PLC-User weiter.

Wir haben bereits den Erfolg, dass Rote Rechtecke reingezeichnet werden.

Hierbei fällt auf, dass diese nicht richtig positioniert werden. Die landen auf dem Bauteil und nicht auf dem Verweis.

Weiß jemand, wo die Koordinaten vom den Querverweis gespeichert ist, damit man diese übernehmen kann?

Translate:
I've been working with ChatGPT for a long time and am trying to get the link to work.

We are continuing to work on the PLC-User script.

We have already succeeded in drawing red rectangles.

However, it is noticeable that these are not positioned correctly. They end up on the component and not on the reference.

Does anyone know where the coordinates of the cross-reference are stored so that they can be transferred? 

Translated with DeepL.com (free version)

@plc-user

Excellent work on the position list — this is exactly the right foundation. I can bring two missing pieces.

**1. The Qt API you were looking for: `QPdfEngine::drawHyperlink`**

The Qt PDF engine already supports link annotations internally via a private method:

```cpp
void QPdfEngine::drawHyperlink(const QRectF &r, const QUrl &url)
```

It is accessible (unofficially) by casting the paint engine after `diagram->render()`:

```cpp
#include <private/qpdf_p.h>

// After diagram->render(painter, ...) on each page:
if (printer->outputFormat() == QPrinter::PdfFormat) {
    auto *pdfEngine = dynamic_cast<QPdfEngine*>(painter->paintEngine());
    if (pdfEngine) {
        // painter->worldTransform() captures the scale applied by render()
        // Use it to map scene coordinates -> printer coordinates
        QTransform t = painter->worldTransform();
        for (auto &link : xrefLinksForThisPage) {
            QRectF printerRect = t.mapRect(link.sourceRect);
            QUrl   target(QString("page=%1&x=%2&y=%3")
                          .arg(link.targetPage)
                          .arg(link.targetX)
                          .arg(link.targetY));
            pdfEngine->drawHyperlink(printerRect, target);
        }
    }
}
```

This is private API (requires Qt private headers: `QT += gui-private` in .pro or `find_package(Qt6 ... PRIVATE)` in CMake), so it could theoretically change between Qt versions — but it has been present and stable since Qt 4 and is still there in Qt 6.11. QTBUG-44563 (open since 2015) tracks the request for a public API.

The `painter->worldTransform()` is the key to solving your zoom/fit_page problem: after each `diagram->render(painter, targetRect, sourceRect, Qt::KeepAspectRatio)`, the painter's world transform already encodes the exact scale and offset applied. Mapping the scene-space link rectangles through this transform gives the correct printer-space coordinates automatically.

**2. An important correctness issue: page number vs. folio label**

Using `page=N` as the link target works if folio order never changes. But QET supports two different ways to identify folios:

- `%f` — position in the tree (physical page number in the PDF). If the user reorders folios, all links break.
- `%F` — the folio label, stable regardless of position in the tree.

If users configure their XRef formulas with `%F` instead of `%f`, they expect links to follow the folio wherever it moves. A link based on `page=N` does not honour this.

The robust solution is to build a **named destination dictionary** before the print pass:
```
folio_label -> (physical_page_number, y_position)
```
Then use the label as the link target instead of the page number. Unfortunately `drawHyperlink` only accepts a `QUrl`, so named internal destinations would require writing raw PDF annotations — which means either a post-processing step (as Alfonso's Python script does) or a third-party library (libmupdf, QPDF).

For a pragmatic first implementation, `page=N` with `drawHyperlink` is a good start — it works correctly as long as the folio order at export time matches the XRef labels. Just worth documenting the limitation.

**Summary**

- `QPdfEngine::drawHyperlink` + `painter->worldTransform()` solves the injection and the coordinate scaling in one step
- Named destinations (for `%F` stability) require a post-processing pass or lib — this is a known limitation of what Qt exposes today
- Your position list code is the right foundation; the missing piece was just how to inject it

Happy to help test or integrate this if you share the patch.

Hi Laurent,
I'm currently working on another feature, and after that I'll be going on vacation with my wife and kids. So unfortunately, I won't be able to get to it anytime soon.
Other than that, I only use AI (Gemini) for all my editing.

Thank you very much. My father-in-law gave me the same advice, and I try to spend as much time with them as possible.