From e1523fd7a0790fc0466e17c839ea220308ce32f5 Mon Sep 17 00:00:00 2001
From: Ruth Comer <10599679+rcomer@users.noreply.github.com>
Date: Thu, 15 Dec 2022 17:58:27 +0000
Subject: [PATCH] Backport PR #24732: Use masked stack to preserve mask info

---
 lib/matplotlib/collections.py                 |   2 +-
 .../test_check_masked_offsets.png             | Bin 0 -> 4078 bytes
 lib/matplotlib/tests/test_collections.py      |  20 ++++++++++++++++++
 3 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 lib/matplotlib/tests/baseline_images/test_collections/test_check_masked_offsets.png

diff --git a/lib/matplotlib/collections.py b/lib/matplotlib/collections.py
index 26514946cb79..b5ac24dd54c7 100644
--- a/lib/matplotlib/collections.py
+++ b/lib/matplotlib/collections.py
@@ -323,7 +323,7 @@ def _prepare_points(self):
                 paths.append(mpath.Path(np.column_stack([xs, ys]), path.codes))
             xs = self.convert_xunits(offsets[:, 0])
             ys = self.convert_yunits(offsets[:, 1])
-            offsets = np.column_stack([xs, ys])
+            offsets = np.ma.column_stack([xs, ys])
 
         if not transform.is_affine:
             paths = [transform.transform_path_non_affine(path)
diff --git a/lib/matplotlib/tests/baseline_images/test_collections/test_check_masked_offsets.png b/lib/matplotlib/tests/baseline_images/test_collections/test_check_masked_offsets.png
new file mode 100644
index 0000000000000000000000000000000000000000..ebac9df75ddb4636def2c1dda3cf332210832d3a
GIT binary patch
literal 4078
zcmeH~Yfw{X8poe-5fBtgD^hgP)oB@5H(XpGAVj-Wk+#TM1wk%p5R4Fx1SJ>2T-+*M
zYK7VDR$M?b)>*_r16kaJds0v%xWG^eQ3B>@1Xdy>5M#&%*ptreuH9*8_M^7_aORwO
z-#PE~|2+TSQ}VmLF)Nn)EeC)Vv3quY2;jg2z@e_ou$Iul(Z|>;v0ztH!T!7>1x)hs
zEQli)&~oz%a<enmGqR4K$j&>q6(5cd!e?eNBEmyAQ!>MX4`*eP30uSPnIS<TA;BTR
zp<C7;EhwO!hztxw{_{6J?>HqeN3?4Ro578?C;0?`C)xhsYPVm_#y*I#JKs6Ls+t}X
z<-9>%C!bx~P5vg+C2D;M;cOK?DcN<>VdXuR%L88dN2}_ed$;3svRl-~M(>n!yw}{x
z0dX}!2A@uRZ;6ZY#@72b;<}3&;oX)`BC5=DQI$QpYvm$<KZrt&*z7im(|Xw9i*p69
z-QWOcUgH6fe|k+VL?cu_efI4711XoZZQHic%Dx(Z7npa`5Qb-G^T%50bz*UdvdamL
zXy-0<whAi?Jpf(3*57}4S|z#af7shWzm~yZ2&V3EcNom49%TcMKWJjp(<H5B0p7ex
zJzd2l^4)j9y`UbFx_5Mb8MwX;IOuZS0lXjwFIfK>IDzZN?>4!-;|S%wlXpew9o7Tu
z%HpRc`Wa)=6IX=DIPtof>BR%tUuWm~_C>R2#ibVl>P*i^rXyL+B+r?dIKq8JhPy8`
zzmeV<A&?J{xU0Dd3F|Hd80XE}Li5DYFMEXk*tLH!V|bDjPip^a_A@@4t$T7#Vl+Ri
z-<nhosog;y3ey791!$ax2W*SHS1q|Eh&)t1RLA5mwp|tm;hKwYX6!>$!cw8O#@`Ku
zXUgQ;OQocUGHw7U^^bc#KZGx@)9CfIsXqexUUN$m`|{+h&gP@{tEjnFlU?KQ2*N5W
z^Vm>&TN<`B3dfU{n9w#|9@9nRBm$1tlcuUreBHeuuy_}#Efx#<uyYcZ?u9Kobvd?2
zMN^C^N3y`FWJ<<_l(LzVD^cgaIeS2=pS@FUZCmudorj$=@BQ(S;rd03q3oKx`I}sv
z<4dk{VSKdg?Kg`r7n74ZW~`hpEF*Bvuabps@i~{HV$ciH!i{?XsFmk6guT%>Y6w*4
zMr|v0)S>)=fGQ7|PiCtRs>Fk)yc8MrXhls$&0jFJ@=l1bqj|Zb+#ZHN8zk~ejZ<S+
zEv!=?hBL+5#Y=1G2sO-@M9apaMfm6PywWL5r}XPl$sH2qF(oFDLK-u#s|THHboP*a
z@ohwK7A<Y_bplIc)HO`}$~)mPug5JbKL<|ed-JCvhwrY=qef{cBz2MH5yB=$Ydvmn
z0A-NJyGHiX7)~~>$L8nO+t}24!IkmYjzZHD>6+#EP5+~K-jbDN)684HFrdGBokwNO
zJ&yf#`5i?*i$%b0$foYQH0>VkDGZT1w-?uB3$iP&$pQ5+=|*ci7;VHY@%=V`v|hka
z1(uyTU4RL`*;|P8O`#7t3G9-NJT{xHr>PBa8Oz59Z-3lYWPCc<F@i|d6Jv-(d;dyN
zwWI42#od>;dHn0K4oeYNNpd*N{UtWcar-b0+m|jDdNg1ES?{lst9|Q4nZCt-#bjfv
z&gym*2lJtcplnRqB0yA%LHgLxMjX^5VWk>^(W~-N{VJJIo70jye2U1Yg#b!1vPp<)
zw_1we8ZKv7<WwA)3I^!E=@azo+5CiM$T9a%WZxX$VuiL-7f`hfP-PM>wL3#pD@G2+
zDCzsloS;#BpHQk9dN=perbK8H){P%e#vHh-2XkPBiT!tE4SPxaLi_<?b&BlOgPe=n
z{hp1n#pGJDZ(@VBlTY&l9_g?%ZN<5pUyg{=evzh(i}nWD$Po>pbib!)Q~x2{(^lby
zJ6U~`2Dbo5;3TR|3Ni9*LG_~hqNy)`cK99|{Ye|7?e6yhA;zoj(7eG3earAeK=>xm
z67D&4?)*U@1YX@vNcZN)%L_4AJWsJb)fU;&aNsKC5)SkRClt#{wVgWYHhiz00Y!7B
zuS5b2Jne4nZVkurK5%$JkZJcQ+^EHT+d}V2fbE#QzCeWfE~0g!|M}T!7tn9yxU*Ko
z-92#kH`4JYow{XT(KLgdR9$6`mL(@li%I@&jzIHIguoJNN|POL6G$1l6cTA&)Tk+H
z2cV<arsvR^^ys3328K!}ImuK_7e4=I^(0o%tnTvBzh%HW7doWcz|#QI^U!|gzxD{|
zr*>leKe6Z*$syvC{IzugfzDbIfCJ93()wI!Wo^K*R?6k_gaieB?8fH++DIZ%C`Rmc
zK~r!9ci_o)DhvFxCTnMdP&=j9H%=JLXE|X~zE)yR?e3fOJ0@12T)35AuhD2)>DojD
z$>OZ(UyerPB8UR3G`L!6Fn?g7jQVj4r*a^4^px=75o?+<kUp-f`^Qt~f7cYU_c7Lp
zBoJ!tjD41bS`ea=W@ss{>@!+BY~HSz6>R>|7J3(#aM!Q!95x*`M_>gm#O~U=Q~2AD
Ge*Z5pYdH`A

literal 0
HcmV?d00001

diff --git a/lib/matplotlib/tests/test_collections.py b/lib/matplotlib/tests/test_collections.py
index 3647e561d2d6..3087703e9daa 100644
--- a/lib/matplotlib/tests/test_collections.py
+++ b/lib/matplotlib/tests/test_collections.py
@@ -1,5 +1,6 @@
 import io
 from types import SimpleNamespace
+from datetime import datetime
 
 import numpy as np
 from numpy.testing import assert_array_equal, assert_array_almost_equal
@@ -1181,3 +1182,22 @@ def test_set_offset_units():
     off0 = sc.get_offsets()
     sc.set_offsets(list(zip(y, d)))
     np.testing.assert_allclose(off0, sc.get_offsets())
+
+
+@image_comparison(baseline_images=["test_check_masked_offsets"],
+                  extensions=["png"], remove_text=True, style="mpl20")
+def test_check_masked_offsets():
+    # Check if masked data is respected by scatter
+    # Ref: Issue #24545
+    unmasked_x = [
+        datetime(2022, 12, 15, 4, 49, 52),
+        datetime(2022, 12, 15, 4, 49, 53),
+        datetime(2022, 12, 15, 4, 49, 54),
+        datetime(2022, 12, 15, 4, 49, 55),
+        datetime(2022, 12, 15, 4, 49, 56),
+    ]
+
+    masked_y = np.ma.array([1, 2, 3, 4, 5], mask=[0, 1, 1, 0, 0])
+
+    fig, ax = plt.subplots()
+    ax.scatter(unmasked_x, masked_y)