Add CICP support to PNG plugin

Signed-off-by: Zach Lewis <zachcanbereached@gmail.com>

Author: zachlewis

src/png.imageio/png_pvt.h

@@ -40,7 +40,7 @@ For further information see the following mailing list threads:
 OIIO_PLUGIN_NAMESPACE_BEGIN
 
 #define ICC_PROFILE_ATTR "ICCProfile"
-
+#define CICP_ATTR "oiio:CICP"
 
 namespace PNG_pvt {
 
@@ -326,6 +326,16 @@ read_info(png_structp& sp, png_infop& ip, int& bit_depth, int& color_type,
 
     interlace_type = png_get_interlace_type(sp, ip);
 
+#ifdef PNG_cICP_SUPPORTED
+    {
+        png_byte cp = 0, tf = 0, mc = 0, fr = 0;
+        if (png_get_cICP(sp, ip, &cp, &tf, &mc, &fr)) {
+            uint8_t cicp[4] = { cp, tf, mc, fr };
+            spec.attribute(CICP_ATTR, TypeDesc(TypeDesc::UINT8, 4), cicp);
+        }
+    }
+#endif
+
 #ifdef PNG_eXIf_SUPPORTED
     // Recent version of PNG and libpng (>= 1.6.32, I think) have direct
     // support for Exif chunks. Older versions don't support it, and I'm not
@@ -698,6 +708,17 @@ write_info(png_structp& sp, png_infop& ip, int& color_type, ImageSpec& spec,
                      (png_uint_32)(yres * scale), unittype);
     }
 
+#ifdef PNG_cICP_SUPPORTED
+    const ParamValue* p = spec.find_attribute(CICP_ATTR,
+                                              TypeDesc(TypeDesc::UINT8, 4));
+    if (p) {
+        const png_byte* vals = static_cast<const png_byte*>(p->data());
+        if (setjmp(png_jmpbuf(sp)))  // NOLINT(cert-err52-cpp)
+            return "Could not set PNG cICP chunk";
+        png_set_cICP(sp, ip, vals[0], vals[1], vals[2], vals[3]);
+    }
+#endif
+
 #ifdef PNG_eXIf_SUPPORTED
     std::vector<char> exifBlob;
     encode_exif(spec, exifBlob, endian::big);

src/png.imageio/pnginput.cpp

@@ -18,7 +18,14 @@ class PNGInput final : public ImageInput {
     const char* format_name(void) const override { return "png"; }
     int supports(string_view feature) const override
     {
-        return (feature == "ioproxy" || feature == "exif");
+        return (feature == "ioproxy"
+#ifdef PNG_eXIf_SUPPORTED
+                || feature == "exif"
+#endif
+#ifdef PNG_cICP_SUPPORTED
+                || feature == "cicp"
+#endif
+        );
     }
     bool valid_file(Filesystem::IOProxy* ioproxy) const override;
     bool open(const std::string& name, ImageSpec& newspec) override;

src/png.imageio/pngoutput.cpp

@@ -24,6 +24,9 @@ class PNGOutput final : public ImageOutput {
         return (feature == "alpha" || feature == "ioproxy"
 #ifdef PNG_eXIf_SUPPORTED
                 || feature == "exif"
+#endif
+#ifdef PNG_cICP_SUPPORTED
+                || feature == "cicp"
 #endif
         );
     }