tdf#131496 vcl image lazy load: speed up vector images with custom pref size

This speeds up the loading of the bugdoc:

- old cost: 6378 ms
- new cost: 1891 ms (30% of baseline)

Images were initially loaded at import time, but commit
acb803b730f2c6bd82e39beab58949ec14f85eb0 (tdf#125591 DOC import:
lazy-load metafiles with explicit size, 2019-06-11) changed this, so
that they are lazy-loaded. That improved performance, but sometimes gave
incorrect results.

Then commit d8371cdfd092c6426c01aae130ea4eaa6d627a6f (tdf#127446 vcl
image lazy-load: fix custom size handling of metafiles, 2019-09-30)
fixed the correctness problem, but the loading was no longer lazy in the
tdf#131496 case.

This is an attempt to bring back lazy-loading for vector-based images,
while maintaining the correct preferred size.

The problem was that the PPT import triggered a vector -> bitmap
conversion during load:

#0  0x00007ffff03c7e36 in ImpGraphic::loadPrepared() (this=this@entry=0x1f88a90) at vcl/source/gdi/impgraph.cxx:1424
#1  0x00007ffff03c72c7 in ImpGraphic::ImplSwapIn() (this=0x1f88a90) at vcl/source/gdi/impgraph.cxx:1444
#2  0x00007ffff03c7535 in ImpGraphic::ensureAvailable() const (this=this@entry=0x1f88a90) at vcl/source/gdi/impgraph.cxx:1402
#3  0x00007ffff03c9481 in ImpGraphic::ImplExportNative(SvStream&) const (this=0x1f88a90, rOStm=...) at vcl/source/gdi/impgraph.cxx:1590
#4  0x00007ffff03bf9a8 in Graphic::ExportNative(SvStream&) const (this=this@entry=0x20534e0, rOStream=...) at vcl/source/gdi/graph.cxx:544
#5  0x00007ffff1c79a28 in svt::EmbeddedObjectRef::SetGraphicToContainer(Graphic const&, comphelper::EmbeddedObjectContainer&, rtl::OUString const&, rtl::OUString const&)
(rGraphic=..., aContainer=..., aName="Object 1", aMediaType="") at svtools/source/misc/embedhlp.cxx:773
#6  0x00007ffff1c79b6f in svt::EmbeddedObjectRef::AssignToContainer(comphelper::EmbeddedObjectContainer*, rtl::OUString const&)
(this=0x207ae90, pContainer=pContainer@entry=0x1f8de40, rPersistName=...) at svtools/source/misc/embedhlp.cxx:369
#7  0x00007ffff239f736 in SdrOle2Obj::Connect_Impl() (this=this@entry=0x20734f0) at svx/source/svdraw/svdoole2.cxx:984
#8  0x00007ffff23a6310 in SdrOle2Obj::Init() (this=this@entry=0x20734f0) at svx/source/svdraw/svdoole2.cxx:695

Try to defer that conversion by not doing a
maVectorGraphicData->getReplacement() in ImpGraphic::ImplSetPrefSize(),
rather just store the preferred size and apply it later when
getReplacement() is called.

This helps, because the above OLE-from-PPT case loads the graphic, but
only to export it as SVM, so it doesn't need a vector -> bitmap
conversion otherwise.

(cherry picked from commit 952cc68929f863784c6b01c9dc071494892877d1)

Change-Id: I24790c0a3e298d5fbb3faff35d529e79cc72845a
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/92156
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/vcl/inc/impgraph.hxx b/vcl/inc/impgraph.hxx
index 90e658c67308..159b70a691e0 100644
--- a/vcl/inc/impgraph.hxx
+++ b/vcl/inc/impgraph.hxx
@@ -75,6 +75,8 @@ private:
 
     GDIMetaFile                  maMetaFile;
     BitmapEx                     maEx;
+    /// If maEx is empty, this preferred size will be set on it when it gets initialized.
+    Size                         maExPrefSize;
     ImpSwapInfo                  maSwapInfo;
     std::unique_ptr<Animation>   mpAnimation;
     std::shared_ptr<GraphicReader> mpContext;
@@ -232,6 +234,9 @@ private:
 
     void setPdfData(const std::shared_ptr<std::vector<sal_Int8>>& rPdfData);
 
+    /// Gets the bitmap replacement for a vector graphic.
+    BitmapEx getVectorGraphicReplacement() const;
+
     bool ensureAvailable () const;
 
     bool loadPrepared();