From 3590a43fc506afca40a20b09fb6e8007b6dcf5b8 Mon Sep 17 00:00:00 2001
From: Albert Astals Cid <aacid@kde.org>
Date: Wed, 17 Jul 2024 21:56:30 +0200
Subject: [PATCH] pcx: Read 16 color images that are 4bpp and 1 plane

We had code for 1bpp and 4 planes but gimp is generating this format
---
 autotests/read/pcx/indexed4.pcx | Bin 0 -> 506 bytes
 autotests/read/pcx/indexed4.png | Bin 0 -> 593 bytes
 src/imageformats/pcx.cpp        |  42 ++++++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+)
 create mode 100644 autotests/read/pcx/indexed4.pcx
 create mode 100644 autotests/read/pcx/indexed4.png

diff --git a/autotests/read/pcx/indexed4.pcx b/autotests/read/pcx/indexed4.pcx
new file mode 100644
index 0000000000000000000000000000000000000000..d79b033d0db3ab872e198cb3150d32d55f3355e7
GIT binary patch
literal 506
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z(jRn|{Q=$`E=7ah6hz+n>%FsE8vDKBefYlL`+j-jW0HsAo5l)A0cmadrLtLTCo}5B
zX-tKUcDlkBYW4f=x1;k;p=G45-t}(x<MaD#FdSH7z$71&$l#w(5zq(oQGmgPB9uOo
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e>Gr^-;+9L<b(eO$c%Ru2TmawY)bMmJUd0bhv^^{U

literal 0
HcmV?d00001

diff --git a/autotests/read/pcx/indexed4.png b/autotests/read/pcx/indexed4.png
new file mode 100644
index 0000000000000000000000000000000000000000..71f36ead86378ad4aa39b0813b228772d1475629
GIT binary patch
literal 593
zcmeAS@N?(olHy`uVBq!ia0vp^3LwnE3?yBabR7e6l0AZa85pY67#JE_7#My5g&JNk
zFq9fFFuY1&V6d9Oz#v{QXIG#NP{KICC&cy7|KGp={r>vv$HRv&S3JKr=g!<S_cKn<
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zWHAGSo-znCRxGtI0}8U2c>21szhD;>7G*S=BEkn0dgSTi7-DgH>EzSXm=!r(L|qQJ
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zE4LnUl>MK#K%Ci`ZN|YxO2AlPP%UwdC`m~yNwrEYN(E93Mg~SEx(4RDhUOuLmR3My
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literal 0
HcmV?d00001

diff --git a/src/imageformats/pcx.cpp b/src/imageformats/pcx.cpp
index 44a64b0..c3ac535 100644
--- a/src/imageformats/pcx.cpp
+++ b/src/imageformats/pcx.cpp
@@ -344,6 +344,46 @@ static bool readImage4(QImage &img, QDataStream &s, const PCXHEADER &header)
     return true;
 }
 
+static bool readImage4v2(QImage &img, QDataStream &s, const PCXHEADER &header)
+{
+    QByteArray buf(header.BytesPerLine, 0);
+
+    img = imageAlloc(header.width(), header.height(), QImage::Format_Indexed8);
+    img.setColorCount(16);
+
+    if (img.isNull()) {
+        qWarning() << "Failed to allocate image, invalid dimensions?" << QSize(header.width(), header.height());
+        return false;
+    }
+
+    for (int y = 0; y < header.height(); ++y) {
+        if (s.atEnd()) {
+            return false;
+        }
+
+        if (!readLine(s, buf, header)) {
+            return false;
+        }
+
+        uchar *p = img.scanLine(y);
+        if (!p) {
+            return false;
+        }
+
+        for (unsigned int x = 0; x < header.BytesPerLine; ++x) {
+            p[x * 2] = (buf[x] & 240) >> 4;
+            p[x * 2 + 1] = buf[x] & 15;
+        }
+    }
+
+    // Read the palette
+    for (int i = 0; i < 16; ++i) {
+        img.setColor(i, header.ColorMap.color(i));
+    }
+
+    return (s.status() == QDataStream::Ok);
+}
+
 static bool readImage8(QImage &img, QDataStream &s, const PCXHEADER &header)
 {
     QByteArray buf(header.BytesPerLine, 0);
@@ -672,6 +712,8 @@ bool PCXHandler::read(QImage *outImage)
         ok = readImage1(img, s, header);
     } else if (header.Bpp == 1 && header.NPlanes == 4) {
         ok = readImage4(img, s, header);
+    } else if (header.Bpp == 4 && header.NPlanes == 1) {
+        ok = readImage4v2(img, s, header);
     } else if (header.Bpp == 8 && header.NPlanes == 1) {
         ok = readImage8(img, s, header);
     } else if (header.Bpp == 8 && header.NPlanes == 3) {