From b0bd6293366a31f2bd7fa347aa104c326bc2d088 Mon Sep 17 00:00:00 2001
From: Peter Petrik <zilolv@gmail.com>
Date: Tue, 23 Oct 2018 11:11:25 +0200
Subject: [PATCH] fix #19939: render mesh arrows also on the edge of the canvas

---
 src/core/mesh/qgsmeshvectorrenderer.cpp       |  26 ++++++++++++------
 src/core/mesh/qgsmeshvectorrenderer.h         |   8 ++++++
 ...triangle_face_vector_user_grid_dataset.png | Bin 80307 -> 80307 bytes
 ...iangle_vertex_vector_user_grid_dataset.png | Bin 80307 -> 80307 bytes
 4 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/src/core/mesh/qgsmeshvectorrenderer.cpp b/src/core/mesh/qgsmeshvectorrenderer.cpp
index 31d83813987c..5bbe0bd61a0a 100644
--- a/src/core/mesh/qgsmeshvectorrenderer.cpp
+++ b/src/core/mesh/qgsmeshvectorrenderer.cpp
@@ -64,11 +64,21 @@ QgsMeshVectorRenderer::QgsMeshVectorRenderer( const QgsTriangularMesh &m,
   , mCfg( settings )
   , mDataOnVertices( dataIsOnVertices )
   , mOutputSize( size )
+  , mBufferedExtent( context.extent() )
 {
   // should be checked in caller
   Q_ASSERT( !mDatasetValuesMag.empty() );
   Q_ASSERT( !std::isnan( mMinMag ) );
   Q_ASSERT( !std::isnan( mMaxMag ) );
+
+  // we need to expand out the extent so that it includes
+  // arrows which start or end up outside of the
+  // actual visible extent
+  double extension = context.convertToMapUnits( mMaxMag, QgsUnitTypes::RenderPixels );
+  mBufferedExtent.setXMinimum( mBufferedExtent.xMinimum() - extension );
+  mBufferedExtent.setXMaximum( mBufferedExtent.xMaximum() + extension );
+  mBufferedExtent.setYMinimum( mBufferedExtent.yMinimum() - extension );
+  mBufferedExtent.setYMaximum( mBufferedExtent.yMaximum() + extension );
 }
 
 QgsMeshVectorRenderer::~QgsMeshVectorRenderer() = default;
@@ -91,7 +101,7 @@ void QgsMeshVectorRenderer::draw()
   pen.setColor( mCfg.color() );
   painter->setPen( pen );
 
-  const QList<int> trianglesInExtent = mTriangularMesh.faceIndexesForRectangle( mContext.extent() );
+  const QList<int> trianglesInExtent = mTriangularMesh.faceIndexesForRectangle( mBufferedExtent );
 
   if ( mCfg.isOnUserDefinedGrid() )
     drawVectorDataOnGrid( trianglesInExtent );
@@ -180,11 +190,11 @@ bool QgsMeshVectorRenderer::calcVectorLineEnd(
 
   vectorLength = sqrt( xDist * xDist + yDist * yDist );
 
-  // Check to see if any of the coords are outside the QImage area, if so, skip the whole vector
-  if ( lineStart.x() < 0 || lineStart.x() > mOutputSize.width() ||
-       lineStart.y() < 0 || lineStart.y() > mOutputSize.height() ||
-       lineEnd.x() < 0   || lineEnd.x() > mOutputSize.width() ||
-       lineEnd.y() < 0   || lineEnd.y() > mOutputSize.height() )
+  // Check to see if both of the coords are outside the QImage area, if so, skip the whole vector
+  if ( ( lineStart.x() < 0 || lineStart.x() > mOutputSize.width() ||
+         lineStart.y() < 0 || lineStart.y() > mOutputSize.height() ) &&
+       ( lineEnd.x() < 0   || lineEnd.x() > mOutputSize.width() ||
+         lineEnd.y() < 0   || lineEnd.y() > mOutputSize.height() ) )
     return true;
 
   return false; //success
@@ -213,7 +223,7 @@ void QgsMeshVectorRenderer::drawVectorDataOnVertices( const QList<int> &triangle
       drawnVertices.insert( i );
 
       const QgsMeshVertex &vertex = vertices.at( i );
-      if ( !mContext.extent().contains( vertex ) )
+      if ( !mBufferedExtent.contains( vertex ) )
         continue;
 
       double xVal = mDatasetValuesX[i];
@@ -240,7 +250,7 @@ void QgsMeshVectorRenderer::drawVectorDataOnFaces( const QList<int> &trianglesIn
       break;
 
     QgsPointXY center = centroids.at( i );
-    if ( !mContext.extent().contains( center ) )
+    if ( !mBufferedExtent.contains( center ) )
       continue;
 
     double xVal = mDatasetValuesX[i];
diff --git a/src/core/mesh/qgsmeshvectorrenderer.h b/src/core/mesh/qgsmeshvectorrenderer.h
index 6ee40f6919e6..d89bd5f0eaaa 100644
--- a/src/core/mesh/qgsmeshvectorrenderer.h
+++ b/src/core/mesh/qgsmeshvectorrenderer.h
@@ -94,6 +94,14 @@ class QgsMeshVectorRenderer
     const QgsMeshRendererVectorSettings &mCfg;
     bool mDataOnVertices = true;
     QSize mOutputSize;
+
+    /**
+     * Canvas extent buffered by vector maximum magnitude
+     * Needed to draw arrows which have
+     * start or end point outside the
+     * visible canvas extent
+     */
+    QgsRectangle mBufferedExtent;
 };
 
 ///@endcond
diff --git a/tests/testdata/control_images/mesh/expected_quad_and_triangle_face_vector_user_grid_dataset/expected_quad_and_triangle_face_vector_user_grid_dataset.png b/tests/testdata/control_images/mesh/expected_quad_and_triangle_face_vector_user_grid_dataset/expected_quad_and_triangle_face_vector_user_grid_dataset.png
index b25f74247c2f2711fc9d7b0c7ce5bf8ac97e7875..0c184aa71c5a2bb9abc1239c8768a85c68ec1a2d 100644
GIT binary patch
delta 1391
zcmb7EeMnSU6u<Ayv!<NsDLZWjYbs1I#MBO?5QEuNW(HOc3KeC&wgUUG+%S5Dh3IaJ
zAgpgrsgXn(^qn>DmJ-77h=tso9W(kT#d6uAFO`Yu)70tQnK$M5$3g>l-o5Ai&c{9P
z_j@!X(2!7{Cob7o8ot|ljvTn?BdPNoihHMcp=uxLMAQEB9VE@Z@PABkfhWb$&m*M$
z#2=)+sg{h7jY0C#3`5DWCdJ)P#c?wa_p4<^YNqvfe&_KC<%i8Jeja>xnU$T|>!)%F
z{FHE*yblE-r*6L@HG102XG?fbAcj%>qa0{OGx>GfJW#7hG6K9MADJ!1u(9R@WHc}<
zh~o+LdP4;ky2w(i{$K<G1E(ZKx{5(cNsDmy7h5(Q)ix{ATNaPbBnS-I!L)T#Eb|Kv
zT+P$q%+5qlp9NZ5>SB(klN>fW$Mz4egGCrSoe8E(<*XGfPp`e$&MA@rg}W<s$Z}5^
z-l>ARetyQmKuCbK!F&j`+OdIVMY2)f^$k4ysTN`e`b7PgLw_z*-ueyCYTFP8_is9=
z=IrMaIgTUGdLNSBzwdzeQx@%CT*eFC$1jVp##IGrKCI&Zp83O#x<<Wi)i1~16q`HM
ziW*Ep_)u{r4$T>z(ofX1waX1#R3oj<>Ss5}$1WXE8hOgNH>quA187bQyb{fH!R=8V
zoE<52cqEyJE?;i6!%W<!W0$iyVP!%02tBF|;}xr|@U-R~+*lFBiGXXRtS@VVp<wTk
zDzDqfi|qRI7Uz)<Z-V4W&ppVf{lOe2?6+JhBRLy(z|z{)iQkRj!nCK;VE9JH*);1x
z0#3u|2?RX>D}B&8jYrbR`m)S)7E5H=mOYWu>~B@+K_YnF0z)xs2@rU=Y0}=3%A!ys
zU!(fE{vxY(A0k{+->0zG9U(i5HbHk&rXr>52__sZFufxwIgF|a4ZS8aEI-C#Q4|xX
z8yG5_eAJ3qY<g55gE2JYZnh#>Cr~+ZjH0a(y=k1VZ!naKG;l;<1OGjbCC7}mXhvNj
z@jg5AdHhCNe%^}HwCmwD80LsmiffO?+yfyalwHY<AyJ16iBg&<oIzbcNl~AX?i%jl
z<83As(OfL(K(ie0N>bZW(US>d?`2#mFr&k+NEYnoCFFbz!kiIVU+a;zsPQx(dlSgk
n8eVu*Y<(R4gygqpbKJH?mV(M-jlI9l&x>$i#hTpKWm5GQwWM@=

delta 815
zcmY*XZAepL6!u=;@``tC(Vzuo`ypX4)Nnt>u(-sk31iJHs1R*b^f|ge7OW5%CV>*M
zy8|gXA}S2Y4EC-@1#<m8w&}kj28)c8*cdIs){M^kZuW8iT;AtA=bYy}=g=~tWfD2`
z$h%#Po2&w;Hw?*0qtIn(T*<v{`1xZEmZXIZ)Fnc`Ou!nmLSC8$rK1U|scG`=)T$qb
z^?|s_Er9Ir$6$yBX*ESeO?AM)!#2bc|6q37(w4@U2jm%*^RY2~wsKa`R06)sAx(8h
z10jqAsnYQYQ4eJ1Y>+AVI5z+M17dC%j5AIc+JlAY*Ahd9UNB^o_nLJqBFjZ}XAXNQ
zG`BAxlGk@UUEo#1nresCJR?t1<1d2<izDn2!(lhk+nbL{FqpcAzyzEA33?(%GaCf%
zQB|ON-(8u=yZvz--^oVT)E!jzr+PJ2s%t{Wn5a&;!2dXyT-UZN&_dFR0?pWA751-{
zprxXK^9{~np~cD;5%sxX7uR?UHEt8g<81ag9oCDO)mj%C7C|}8RM$kp_*jUJk6kxv
zsulD;3*@I{$WGcJOnmhPd=o&4HNk_6&C&N}C{5W|vHuZjiu7V#&N9OK{qDaM{zPB;
zSxa^+x<F1QDqqloPM(qf_!*R$9u``zbwUK~XZ#5SC8|!h;y!G3_ElUFi~U)@az$s+
zd|86PQx~>kH?Wsyu=6`o3gS7?OT{IT4^`Ve(uY7#F#0I3W_W4B6g#Yc4}mFij<&y&
z@$Ep5*%nWr!D&2ai5YuSBwNqBo7oNH2_?G);f%w)^Ilrr<B@JP;Ma4|>zX@odgM2<
C7IEDG

diff --git a/tests/testdata/control_images/mesh/expected_quad_and_triangle_vertex_vector_user_grid_dataset/expected_quad_and_triangle_vertex_vector_user_grid_dataset.png b/tests/testdata/control_images/mesh/expected_quad_and_triangle_vertex_vector_user_grid_dataset/expected_quad_and_triangle_vertex_vector_user_grid_dataset.png
index 856e316703b694db2417da48b3ac5a2918f17b55..2ebb9a7932f5c970623f9fb59cc2900f38cc376d 100644
GIT binary patch
delta 1521
zcmbtUdr(wm6hHTJVX*}kWEX+eSZ4>JkXWqbF~sgN<b)9c&ETj&?5ZeZ<TjC%ppr)5
zqm9caNyS^!#){WvT&FNr3@C;b#W2j2$3!77!9`vI+xP7Zn>j<%Oy{5P%y-Xs&iVb$
z?_AEva7LzjJtf|!@PyI+KA<QHoW&lnCO{6J>t6t`06Fq6c#mtPim3ea*8GL}c{qRK
zLr`nWSyitf@{J6zVytm!C@gnh#j4&H+_};MCw4@`<oz*N_fjmPT0~s6Fq7hPY;<l+
z`&plxC`xgL8<3=zSj|10Mc01Zg6bP={iN%H;Bj+uTM4ukW4WF(j>B!7AD^sBX)oLG
zDtz#L7lf<#0EJj#5VLD&?GAK6A8R%8doQ}KH@N4kBjM_|H9-1))F=woG(E}p4pxGu
zLI-@oa#mGtH#0c_7fbVDf0#F*ni~mdq;Vyymhf%u?18t855{}LD5lwyClI;9=B#{_
zwJjA%46dlM!xoKP{@MM?g(_TW&Qj<J2S?H?m`vzWr#sIt{1w=qcN&dPv8={XU>q5O
zhKd5ve^CgN<M&WZry4ml3sFUfL?HI^h1uyz80x(Z(-THk<;j<C*$L5Uhhdq$fK{cS
zyqm5lq)v!jTCVbSCyy-FMDn^-tcKwQ#>7Kn&ZnsAOgVpk?jaoABqzyE`pKwd&gZ9U
znn&ig^-uvi*qAJxnR)=<<fbnsv7D7h_W@}|^2~F%1(esuNChr#=Fg8Z%2?Y#<eU2;
zv$hqa&jyqBBnBp+MtcCz_9!4g7mZN2r%VSgW94AQfa-YZ;wST+A|ZuUUE-S-7T{tT
zg6!x(#FmSY_PUL;CC(fem#H-m{VN_BVpvits;P=)H9{`6y^iMhb+$v1CIJR}ZXy3u
z!K_BcebRB77MM&X_^$Y4sMQ_>qQ2oxPqP{Y68G704V{IwWbE!AP_|bMUCj-Dm&2YT
zMm;w8Cs9QVlJzrOTi2Jglql;|MhZL_8?i)_4U%u&39)-~pd>8`DeE`l^fJ!rw@f<U
z#CV;{PJ^a%C0G+C%Nu)V5gyiO;H%tdzQg(OyHInX**nK6#^v&63a^a<we}243AW<5
z65($5ua*qN@d@1kujdwlgJ=cjB8(IF)zQ+&09zhd^K2pJoorAh?nYUqBGg^`6esJi
zr=?3V;J(HOwtZ9%VsBqo<%Z)|a}fi2+G9x$;&;Jo>A6_!t8uUhV~J-qYtfjA;Rc5S
z2^AhoQjz;P_$nfZ;<{_?QN(~ZS2|iod;BZ#BgIHH?8_Y+H~d%7{@m9S2HK-=cbxeb
zVW9>){{Z_uXP7e3VzNa9EHN@<tW-!wXTi}`%&LO8(b;RXpycf&_@${H5*HCDIl;nV
zn#l>OzJTW!$D5wGkN0{Sw;G`fp(wS7tv2J`835NAr0ogOmGP(>G|FpCAl?uE%M;#O
V;W(sk(>sxVBVLROuMA5%^cVgDEDrzx

delta 884
zcmYjPdq|T}6hGf~bv~xk+;BR<nO261`=f`E(h4;#o%VtVqn4FPnO{%{X)+25DbwrK
zjF60okg`&5HVn&0m?SgNum`A#AjwQ|&RmLa-ET|r!pHfY-#PdE&OP6uRz$6+VH=0}
zO4`HKa6}vHMhDkNGa@r!<a0M%-mZeamRF!j$^b84KjS6Dm2&i!yD<p0UM+k_blRtM
zLS66>^QhuYD(3x2Ynw;Z{oErk%x<qe{y`yNF;9SfdC5uJtQH{$>yx}S$r*68xE%Zf
zgRy=mDn9$Ih7`9S6c3rY$d~qBv8nkv)+^jOP6Q4I=@<;I=tGj+>UxlPNwNL~Yg&Q%
z6f)HrLikd(mxt5`WC|sS5NYh%C==khs%Os6sc?p<d!=IAtc47H7!MYS(b_hJR|3az
z|CPLB6Vu`Rg9evW<BF8;M>(mKtJkSE#egC-9RAK(!7|Anw?zCK128X>>^hbMhL!<h
z$j&3>Kai^I_+Btpmw>}=UzHQ2*dd<X!?IP9f%(}P(s4S7%~TS1APaIT>xjjMF(2uY
zPoz<w8bp{^lAld%<Wk9k?GG4|W5`T`LK3rkA6Tc%MBBfCl$%hvpkXopT3a5Fn>(cB
z7C=hQ6+rG1tj}c=L8NFlB4DudEs*SVXZrpNg^-?KjP)Hdq3idLtDvdO01NYTSRW=4
zqG=be5kqY$=C`<7@uPWtuUThum#d`r2A(iC#JL)Bq8gLZw!!<1Q9BtAq8Ufj^u3NT
z5yBOgp`rdmMa++8eu6W;IC6(WHT@+w*|KR#&**Q=YglkARgDQ+aSU&!n(<bK;~5U4
zsT1uCYZ+Fs0$D<>83&@~$v8%*FxrQtPDIk$=|{{@qqi-+%pRuob1vI!bJ^*|e#U1~
znf-<cm7UPpg=II!bKI#=kFX%$Q2^xvxjPzfG$8J)Ncc5IO$?VWT|qieIc`4Whz;Da
QEQ~WXNtgI?&&lim0OQwMod5s;