Add raw encoders/decoders for 2 channel RG format

Tests/test_file_vtf.py

@@ -74,14 +74,14 @@ def test_get_texture_size(
         ("Tests/images/vtf_i8.png", "Tests/images/vtf_i8.vtf", "L", 0.0),
         ("Tests/images/vtf_a8.png", "Tests/images/vtf_a8.vtf", "L", 0.0),
         ("Tests/images/vtf_ia88.png", "Tests/images/vtf_ia88.vtf", "LA", 0.0),
-        # (
+        (
-        #         "Tests/images/vtf_RG.png",
+                "Tests/images/vtf_uv88.png",
-        #         "Tests/images/vtf_RG.vtf", "RGB",
+                "Tests/images/vtf_uv88.vtf", "RGB",
-        #         0.0),
+                0.0),
         ("Tests/images/vtf_rgb888.png", "Tests/images/vtf_rgb888.vtf", "RGB", 0.0),
         ("Tests/images/vtf_bgr888.png", "Tests/images/vtf_bgr888.vtf", "RGB", 0.0),
         ("Tests/images/vtf_dxt1.png", "Tests/images/vtf_dxt1.vtf", "RGBA", 3.0),
-        ("Tests/images/vtf_rgba8888.png", "Tests/images/vtf_rgba8888.vtf", "RGBA", 0.1),
+        ("Tests/images/vtf_rgba8888.png", "Tests/images/vtf_rgba8888.vtf", "RGBA", 0),
     ],
 )
 def test_vtf_loading(

src/PIL/VtfImagePlugin.py

@@ -230,14 +230,7 @@ def _write_image(fp: BufferedIOBase, im: Image.Image, pixel_format: VtfPF):
         im = im.convert("LA")
     elif pixel_format == VtfPF.UV88:
         encoder = "raw"
-        if im.mode == "RGB" or im.mode == "RGBA":
+        encoder_args = ("RG", 0, 0)
-            r, g, *_ = im.split()
-            im = Image.merge("LA", (r, g))
-        elif im.mode == "LA":
-            pass
-        else:
-            raise VTFException(f"Cannot encode {im.mode} as {pixel_format}")
-        encoder_args = ("LA", 0, 0)
     else:
         raise VTFException(f"Unsupported pixel format: {pixel_format!r}")
 
@@ -327,7 +320,7 @@ class VtfImageFile(ImageFile.ImageFile):
         elif pixel_format in (VtfPF.BGRA8888,):
             tile = ("raw", (0, 0) + self.size, data_start, ("BGRA", 0, 1))
         elif pixel_format in (VtfPF.UV88,):
-            tile = ("raw", (0, 0) + self.size, data_start, ("LA", 0, 1))
+            tile = ("raw", (0, 0) + self.size, data_start, ("RG", 0, 1))
         elif pixel_format in L_FORMATS:
             tile = ("raw", (0, 0) + self.size, data_start, ("L", 0, 1))
         elif pixel_format in LA_FORMATS:

src/libImaging/Pack.c

@@ -242,6 +242,17 @@ packLA(UINT8 *out, const UINT8 *in, int pixels) {
         in += 4;
     }
 }
+static void
+packRG(UINT8 *out, const UINT8 *in, int pixels) {
+    int i;
+    /* LA, pixel interleaved */
+    for (i = 0; i < pixels; i++) {
+        out[0] = in[R];
+        out[1] = in[G];
+        out += 2;
+        in += 4;
+    }
+}
 
 static void
 packLAL(UINT8 *out, const UINT8 *in, int pixels) {
@@ -491,7 +502,7 @@ copy3(UINT8 *out, const UINT8 *in, int pixels) {
 static void
 copy4(UINT8 *out, const UINT8 *in, int pixels) {
     /* RGBA, CMYK quadruples */
-    memcpy(out, in, 4 * pixels);
+    memcpy(out, in, pixels * 4);
 }
 
 static void
@@ -580,6 +591,7 @@ static struct {
     {"RGB", "BGRX", 32, ImagingPackBGRX},
     {"RGB", "XBGR", 32, ImagingPackXBGR},
     {"RGB", "RGB;L", 24, packRGBL},
+    {"RGB", "RG", 16, packRG},
     {"RGB", "R", 8, band0},
     {"RGB", "G", 8, band1},
     {"RGB", "B", 8, band2},
@@ -592,6 +604,7 @@ static struct {
     {"RGBA", "BGRA", 32, ImagingPackBGRA},
     {"RGBA", "ABGR", 32, ImagingPackABGR},
     {"RGBA", "BGRa", 32, ImagingPackBGRa},
+    {"RGBA", "RG", 16, packRG},
     {"RGBA", "R", 8, band0},
     {"RGBA", "G", 8, band1},
     {"RGBA", "B", 8, band2},

src/libImaging/Unpack.c

@@ -424,6 +424,18 @@ unpackLA(UINT8 *_out, const UINT8 *in, int pixels) {
     }
 }
 
+static void
+unpackRG(UINT8 *_out, const UINT8 *in, int pixels) {
+    int i;
+    /* LA, pixel interleaved */
+    for (i = 0; i < pixels; i++) {
+        _out[R] = in[0];
+        _out[G] = in[1];
+        in += 2;
+        _out += 4;
+    }
+}
+
 static void
 unpackLAL(UINT8 *_out, const UINT8 *in, int pixels) {
     int i;
@@ -1547,6 +1559,9 @@ static struct {
     {"PA", "PA", 16, unpackLA},
     {"PA", "PA;L", 16, unpackLAL},
 
+    /*2 channel to RGB/RGBA*/
+    {"RGB", "RG", 16, unpackRG},
+    {"RGBA", "RG", 16, unpackRG},
     /* true colour */
     {"RGB", "RGB", 24, ImagingUnpackRGB},
     {"RGB", "RGB;L", 24, unpackRGBL},