1 files changed, 136 insertions, 0 deletions
diff --git a/lib/extras/enc/encode.cc b/lib/extras/enc/encode.cc
new file mode 100644
index 0000000..dc593d2
--- /dev/null
+++ b/lib/extras/enc/encode.cc
@@ -0,0 +1,136 @@
+// Copyright (c) the JPEG XL Project Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "lib/extras/enc/encode.h"
+
+#include <locale>
+
+#if JPEGXL_ENABLE_APNG
+#include "lib/extras/enc/apng.h"
+#endif
+#if JPEGXL_ENABLE_EXR
+#include "lib/extras/enc/exr.h"
+#endif
+#if JPEGXL_ENABLE_JPEG
+#include "lib/extras/enc/jpg.h"
+#endif
+#include "lib/extras/enc/npy.h"
+#include "lib/extras/enc/pgx.h"
+#include "lib/extras/enc/pnm.h"
+#include "lib/jxl/base/printf_macros.h"
+
+namespace jxl {
+namespace extras {
+
+Status Encoder::VerifyBasicInfo(const JxlBasicInfo& info) const {
+  if (info.xsize == 0 || info.ysize == 0) {
+    return JXL_FAILURE("Empty image");
+  }
+  if (info.num_color_channels != 1 && info.num_color_channels != 3) {
+    return JXL_FAILURE("Invalid number of color channels");
+  }
+  if (info.alpha_bits > 0 && info.alpha_bits != info.bits_per_sample) {
+    return JXL_FAILURE("Alpha bit depth does not match image bit depth");
+  }
+  if (info.orientation != JXL_ORIENT_IDENTITY) {
+    return JXL_FAILURE("Orientation must be identity");
+  }
+  return true;
+}
+
+Status Encoder::VerifyPackedImage(const PackedImage& image,
+                                  const JxlBasicInfo& info) const {
+  if (image.pixels() == nullptr) {
+    return JXL_FAILURE("Invalid image.");
+  }
+  if (image.stride != image.xsize * image.pixel_stride()) {
+    return JXL_FAILURE("Invalid image stride.");
+  }
+  if (image.pixels_size != image.ysize * image.stride) {
+    return JXL_FAILURE("Invalid image size.");
+  }
+  size_t info_num_channels =
+      (info.num_color_channels + (info.alpha_bits > 0 ? 1 : 0));
+  if (image.xsize != info.xsize || image.ysize != info.ysize ||
+      image.format.num_channels != info_num_channels) {
+    return JXL_FAILURE("Frame size does not match image size");
+  }
+  if (info.bits_per_sample >
+      PackedImage::BitsPerChannel(image.format.data_type)) {
+    return JXL_FAILURE("Bit depth does not fit pixel data type");
+  }
+  return true;
+}
+
+Status SelectFormat(const std::vector<JxlPixelFormat>& accepted_formats,
+                    const JxlBasicInfo& basic_info, JxlPixelFormat* format) {
+  const size_t original_bit_depth = basic_info.bits_per_sample;
+  size_t current_bit_depth = 0;
+  size_t num_alpha_channels = (basic_info.alpha_bits != 0 ? 1 : 0);
+  size_t num_channels = basic_info.num_color_channels + num_alpha_channels;
+  for (;;) {
+    for (const JxlPixelFormat& candidate : accepted_formats) {
+      if (candidate.num_channels != num_channels) continue;
+      const size_t candidate_bit_depth =
+          PackedImage::BitsPerChannel(candidate.data_type);
+      if (
+          // Candidate bit depth is less than what we have and still enough
+          (original_bit_depth <= candidate_bit_depth &&
+           candidate_bit_depth < current_bit_depth) ||
+          // Or larger than the too-small bit depth we currently have
+          (current_bit_depth < candidate_bit_depth &&
+           current_bit_depth < original_bit_depth)) {
+        *format = candidate;
+        current_bit_depth = candidate_bit_depth;
+      }
+    }
+    if (current_bit_depth == 0) {
+      if (num_channels > basic_info.num_color_channels) {
+        // Try dropping the alpha channel.
+        --num_channels;
+        continue;
+      }
+      return JXL_FAILURE("no appropriate format found");
+    }
+    break;
+  }
+  if (current_bit_depth < original_bit_depth) {
+    JXL_WARNING("encoding %" PRIuS "-bit original to %" PRIuS " bits",
+                original_bit_depth, current_bit_depth);
+  }
+  return true;
+}
+
+std::unique_ptr<Encoder> Encoder::FromExtension(std::string extension) {
+  std::transform(
+      extension.begin(), extension.end(), extension.begin(),
+      [](char c) { return std::tolower(c, std::locale::classic()); });
+#if JPEGXL_ENABLE_APNG
+  if (extension == ".png" || extension == ".apng") return GetAPNGEncoder();
+#endif
+
+#if JPEGXL_ENABLE_JPEG
+  if (extension == ".jpg") return GetJPEGEncoder();
+  if (extension == ".jpeg") return GetJPEGEncoder();
+#endif
+
+  if (extension == ".npy") return GetNumPyEncoder();
+
+  if (extension == ".pgx") return GetPGXEncoder();
+
+  if (extension == ".pam") return GetPAMEncoder();
+  if (extension == ".pgm") return GetPGMEncoder();
+  if (extension == ".ppm") return GetPPMEncoder();
+  if (extension == ".pfm") return GetPFMEncoder();
+
+#if JPEGXL_ENABLE_EXR
+  if (extension == ".exr") return GetEXREncoder();
+#endif
+
+  return nullptr;
+}
+
+}  // namespace extras
+}  // namespace jxl