mORMot Open Source

UPDATE 2022-06-09

UPDATE 2018-02-02

Hi all,
good news, I have finally made a somewhat big step ahead in clipping implementation.

It is a quite long explanation.. posting code.. functions.. would be difficult, so I share my entire SynPDF.pas
You can test output using test_libuemf_ref.emf and HRVPSDPrintForm.emf

I have problems sharing the reference emf, google drive thinks it contains a virus (but it doesn't) and warns the user before download

There are some differences from standard version, but I think that who is interested will find it useful.

I quote some people involved, hoping they will be notified and come to see:

I think that also davidheffernan problem with multiple metafiles, could be related to clipping, because in my HRVPSDPrintForm.emf test I had a similar problem..

Use it as you like, I got a great improvement with this, I hope that someone else will get it too.

Feel free to ask for explanations if something is not clear, any comment are welcome.

Essentially it is the standard version 1.18.4051 of 2017-12-06 (yesterday) with some differences:

In december 2015 I implemented my function to handle EMR_ARC, EMR_CHORD, EMR_PIE, EMR_ARCTO and I still have not replaced it with ProHolz version
In november 2016 I have integrated some code from JeanMilost about FontFallBackNames and KerningHHorzScale and some code from Niki about dynamic load of UNISCRIBE

All other differences are mine, you will find:

a new set of functions absI2X, absI2Y, absRectI, absBoxI to calc I2X coordinates with absolute reference to page origin (not using WorldTransform), used in ExtSelectClipRgn

a new procedure RectangleClockWise handy for special fill/clip operations with different winding rules

a new InPath flag in TPdfEnumState, to handle operations between EMR_BEGINPATH and EMR_ENDPATH

MetaRgn and ClipRgn in TPdfEnumState and also fInitMetaRgn in TPdfEnum are now TRect instead of TPdfBox to handle clipping objects in logical units

I have also defined the types for brush (TPdfEnumStateBrush) and font (TPdfEnumStateFont) outside TPdfEnumState

some properties and changed some property setter for some internal variable, in SetFillColor(), SetStrokeColor(), SetPenWidth() added test for invalid value -1 before to write to pdf, SetInLined() handles Stroke if needed;

procedure RestoreDC now handles the DC number parameter and (most important) clear the Clip Path if restored DC had a NULL Clip Path;

a new procedure ResetClipPath to clear the Clip Path on PDF and invalidate colors, styles and font, you can't enlarge Clip path on PDF, only reduce it, so the only solution is to restore the NULL Clip Path and apply a new one;

a new procedure InvalidateColorsAndStyle, just a wrapper for fFillColor := -1; fStrokeColor := -1; fPenStyle := -1; fPenWidth := -1;

a new procedure ExtCreatePen to handle a little more the EMR_EXTCREATEPEN record, added basic support for PenStyle = PS_USERSTYLE (emulated with PS_DASH), sets a default pen color black if brush style not in [BS_SOLID, BS_HATCHED] (should use patterns..), sets a default pen width = 1 if brush style in [BS_DIBPATTERN, BS_DIBPATTERNPT, BS_HATCHED, BS_PATTERN], sets pen style to PS_NULL if brush style = BS_NULL

procedure SetMetaRgn now clear the Clip Path on PDF and updates MetaRgn variable

Now let's see the clipping core functions:

IntersectClipRect: now updates the Clip Path on PDF intersecting the rect passed and updates the internal ClipRgn variable
ExcludeClipRect: Added support for EMR_EXCLUDECLIPRECT, updates the Clip Path on PDF excluding the rect passed but does not update the internal ClipRgn (we keep the largest bound rect)
SelectClipPath: Added support for EMR_SELECTCLIPPATH (mode RGN_AND), updates the Clip Path on PDF with the path plotted (but still not painted), but    does not update the internal ClipRgn (because we have no info on path applied)
ExtSelectClipRgn: Added support for EMR_EXTSELECTCLIPRGN (modes RGN_COPY and RGN_AND), intersect or replace the Clip Path on PDF with the rect list passed and updates the internal ClipRgn variable

some changes in procedure TextOut:

• excluded the test on white brush color for opaque background, because white is not transparent;

• inverted the test on font background color, I think it was wrong;

• forced the brush color to font background color for opaque background;

• changed the dimensions of background rectangle because in some cases there was uncovered zones, I have tried to make it automatic but it can be improved and it should be tested with many other fonts styles and dimensions;

• deleted some uselse commands for clip rectangle;

• added silent paint (NewPath) after the Canvas.Clip command, but (WARNING!!) deleted it from FillRectangle();

• deleted the entire block who save graphic state, change clipping, restore graphic state.. if nothing put marks on pdf between clip and restore.. all of this is useless

some changes to EnumEMFFunc function:

EMR_LINETO:
- set Moved to true instead of false because LineTo does move the current position on PDF
- tested the new property InLined for Stroke management

EMR_POLYGON, EMR_POLYLINE, EMR_POLYGON16, EMR_POLYLINE16:
- set Moved to true instead of false because LineTo does move the current position on PDF
- tested the new property InLined to avoid the paint (stroke or fill or silent)

EMR_POLYBEZIER, EMR_POLYBEZIER16, EMR_POLYBEZIERTO, EMR_POLYBEZIERTO16, EMR_POLYLINETO, EMR_POLYLINETO16, EMR_POLYDRAW, EMR_POLYDRAW16:
- set Moved to true instead of false because LineTo does move the current position on PDF

EMR_BEGINPATH, EMR_ENDPATH:
- management of new flag InPath true/false

EMR_FILLPATH:
- forced ClosePath before fill, unfortunately doesn't exists a direct PDF command for Close + Fill

EMR_STROKEPATH:
- made silent paint alternative to Stroke

EMR_STROKEANDFILLPATH:
- forced ClosePath before paint (stroke or fill or silent), unfortunately doesn't exists a direct PDF command for Close + Fill
- made silent paint alternative to Stroke and/or Fill

and finally a little optimization in TextRect()
- repaced MoveTo, LineTo, LineTo, LineTo and CloePath with Rectangle

Merry Christmas from Italy
MtwStark

P.S.
sorry for poor english or bad code..

EDIT: Jump to the end of the page this post is superseeded!

Hello,
I recently had this problem, with introduction of enhanced clipping process by Achim Kalwa, I noticed invalid clipping when rendering metafiles.

They are now partially clipped out without reason, with previous version the clipping of same files was correct.

I have digged a bit and found that the problem is the new ExtSelectClipRgn function because of the transformation of clipping regions using WorldTransform in functions I2X and I2Y

I think that clipping regions are absolute (Window relative?) and they do not need to be shifted/rotated/scaled.

in ExtSelectClipRgn there is a call to BoxI function who calls RectI who calls I2X and I2Y where the clip region is shifted and scaled using FWorldOffsetX/Y and GetWorldFactorX/Y

the resulting clipping region is not correct.

I have simply avoided the BoxI call and calculated the CliptRect manually and it works fine.
This is the modified loop in the ExtSelectClipRgn:

    for i := 0 to RGNs^.rdh.nCount - 1 do begin
      Move(Rgns^.Buffer[i * SizeOf(TRect)], RCT, SizeOf(RCT));
      Inc(RCT.Bottom);
{$IFDEF TMW_TEST_NEW_CLIPRGN}

      // MTW WRONG ORIGIN AND SCALING OF CLIP REGIONS
      // seems that clip region is window relative, not world relative

      with Canvas do begin
        ClipRect.Left := FOffsetXDef + ViewOffsetX(RCT.Left) * FDevScaleX ;//*
        ClipRect.Top := FPage.GetPageHeight - FOffsetYDef - ViewOffsetY(RCT.Top) * FDevScaleY;
        ClipRect.Width := (ViewOffsetX(RCT.Right - 1) - ViewOffsetX(RCT.Left)) * FDevScaleX  ;//*
        ClipRect.Height := (ViewOffsetY(RCT.Top) - ViewOffsetY(RCT.Bottom - 1) ) * FDevScaleY;
      end;

{$ELSE}
      ClipRect := Canvas.BoxI(RCT, False);
{$ENDIF}
      Canvas.Rectangle(ClipRect.Left, ClipRect.Top, ClipRect.Width, ClipRect.Height);
    end;

if the problem is spread across other portions of library it could be interesting to add a flag with default to BoxI, RectI, I2X and I2Y, to exclude WorldOffset and WorldFactor from the calc.

I hope this could be of any help for someone.

Has anyone had my same problem and can confirm my intuition?

thanks
regards