testrender: output jpg/gif/png in sRGB (#758)

Just like we recently did for testshade.

Author: lgritz

src/testrender/testrender.cpp

@@ -34,6 +34,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <cmath>
 
 #include <OpenImageIO/imageio.h>
+#include <OpenImageIO/imagebuf.h>
+#include <OpenImageIO/imagebufalgo.h>
 #include <OpenImageIO/argparse.h>
 #include <OpenImageIO/strutil.h>
 #include <OpenImageIO/timer.h>
@@ -655,7 +657,10 @@ int main (int argc, const char *argv[]) {
 
     double setuptime = timer.lap ();
 
+    // Local memory for the pixels
     std::vector<Color3> pixels(xres * yres, Color3(0,0,0));
+    // Make an ImageBuf that wraps it ('pixels' still owns the memory)
+    ImageBuf pixelbuf (ImageSpec(xres, yres, 3, TypeDesc::FLOAT), pixels.data());
 
     // Create shared counter to iterate over one scanline at a time
     Counter scanline_counter(errhandler, yres, "Rendering");
@@ -664,23 +669,31 @@ int main (int argc, const char *argv[]) {
     for (int i = 0; i < num_threads; i++)
         workers.add_thread(new std::thread (scanline_worker, std::ref(scanline_counter), std::ref(pixels)));
     workers.join_all();
+    double runtime = timer.lap();
 
     // Write image to disk
-    ImageOutput* out = ImageOutput::create(imagefile);
-    ImageSpec spec(xres, yres, 3, TypeDesc::HALF);
-    if (out && out->open(imagefile, spec)) {
-        out->write_image(TypeDesc::TypeFloat, &pixels[0]);
-    } else {
-        errhandler.error("Unable to write output image");
+    if (Strutil::iends_with (imagefile, ".jpg") ||
+        Strutil::iends_with (imagefile, ".jpeg") ||
+        Strutil::iends_with (imagefile, ".gif") ||
+        Strutil::iends_with (imagefile, ".png")) {
+        // JPEG, GIF, and PNG images should be automatically saved as sRGB
+        // because they are almost certainly supposed to be displayed on web
+        // pages.
+        ImageBufAlgo::colorconvert (pixelbuf, pixelbuf,
+                                    "linear", "sRGB", false, "", "");
     }
-    delete out;
+    pixelbuf.set_write_format (TypeDesc::HALF);
+    if (! pixelbuf.write (imagefile))
+        errhandler.error ("Unable to write output image: %s",
+                          pixelbuf.geterror().c_str());
 
     // Print some debugging info
     if (debug1 || runstats || profile) {
-        double runtime = timer.lap();
+        double writetime = timer.lap();
         std::cout << "\n";
         std::cout << "Setup: " << OIIO::Strutil::timeintervalformat (setuptime,2) << "\n";
         std::cout << "Run  : " << OIIO::Strutil::timeintervalformat (runtime,2) << "\n";
+        std::cout << "Write: " << OIIO::Strutil::timeintervalformat (writetime,2) << "\n";
         std::cout << "\n";
         std::cout << shadingsys->getstats (5) << "\n";
         OIIO::TextureSystem *texturesys = shadingsys->texturesys();