1 files changed, 154 insertions, 0 deletions
diff --git a/io_scene_gltf2/io/com/gltf2_io_image.py b/io_scene_gltf2/io/com/gltf2_io_image.py
new file mode 100755
index 00000000..af86daeb
--- /dev/null
+++ b/io_scene_gltf2/io/com/gltf2_io_image.py
@@ -0,0 +1,154 @@
+# Copyright 2018 The glTF-Blender-IO authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+#
+# Imports
+#
+
+import struct
+import zlib
+
+
+class Image:
+    """
+    Image object class to represent a 4-channel RGBA image.
+
+    Pixel values are expected to be floating point in the range of [0.0 to 1.0]
+    """
+
+    def __init__(self, width, height, pixels):
+        self.width = width
+        self.height = height
+        self.channels = 4
+        self.pixels = pixels
+        self.name = ""
+        self.file_format = "PNG"
+
+    def to_png_data(self):
+        buf = bytearray([int(channel * 255.0) for channel in self.pixels])
+
+        #
+        # Taken from 'blender-thumbnailer.py' in Blender.
+        #
+
+        # reverse the vertical line order and add null bytes at the start
+        width_byte_4 = self.width * 4
+        raw_data = b"".join(
+            b'\x00' + buf[span:span + width_byte_4] for span in range(
+                (self.height - 1) * self.width * 4, -1, - width_byte_4))
+
+        def png_pack(png_tag, data):
+            chunk_head = png_tag + data
+            return struct.pack("!I", len(data)) + chunk_head + struct.pack("!I", 0xFFFFFFFF & zlib.crc32(chunk_head))
+
+        return b"".join([
+            b'\x89PNG\r\n\x1a\n',
+            png_pack(b'IHDR', struct.pack("!2I5B", self.width, self.height, 8, 6, 0, 0, 0)),
+            png_pack(b'IDAT', zlib.compress(raw_data, 9)),
+            png_pack(b'IEND', b'')])
+
+    def to_image_data(self, mime_type):
+        if mime_type == 'image/png':
+            return self.to_png_data()
+        raise ValueError("Unsupported image file type {}".format(mime_type))
+
+    def save_png(self, dst_path):
+        data = self.to_png_data()
+        with open(dst_path, 'wb') as f:
+            f.write(data)
+
+
+def create_img(width, height, r=0.0, g=0.0, b=0.0, a=1.0):
+    """
+    Create a new image object with 4 channels and initialize it with the given default values.
+
+    (if no arguments are given, these default to R=0, G=0, B=0, A=1.0)
+    Return the created image object.
+    """
+    return Image(width, height, [r, g, b, a] * (width * height))
+
+
+def create_img_from_pixels(width, height, pixels):
+    """
+    Create a new image object with 4 channels and initialize it using the given array of pixel data.
+
+    Return the created image object.
+    """
+    if pixels is None or len(pixels) != width * height * 4:
+        return None
+
+    return Image(width, height, pixels)
+
+
+def copy_img_channel(dst_image, dst_channel, src_image, src_channel):
+    """
+    Copy a single channel (identified by src_channel) from src_image to dst_image (overwriting dst_channel).
+
+    src_image and dst_image are expected to be image objects created using create_img.
+    Return True on success, False otherwise.
+    """
+    if dst_image is None or src_image is None:
+        return False
+
+    if dst_channel < 0 or dst_channel >= dst_image.channels or src_channel < 0 or src_channel >= src_image.channels:
+        return False
+
+    if src_image.width != dst_image.width or \
+            src_image.height != dst_image.height or \
+            src_image.channels != dst_image.channels:
+        return False
+
+    for i in range(0, len(dst_image.pixels), dst_image.channels):
+        dst_image.pixels[i + dst_channel] = src_image.pixels[i + src_channel]
+
+    return True
+
+
+def test_save_img(image, path):
+    """
+    Save the given image to a PNG file (specified by path).
+
+    Return True on success, False otherwise.
+    """
+    if image is None or image.channels != 4:
+        return False
+
+    width = image.width
+    height = image.height
+
+    buf = bytearray([int(channel * 255.0) for channel in image.pixels])
+
+    #
+    # Taken from 'blender-thumbnailer.py' in Blender.
+    #
+
+    # reverse the vertical line order and add null bytes at the start
+    width_byte_4 = width * 4
+    raw_data = b"".join(
+        b'\x00' + buf[span:span + width_byte_4] for span in range((height - 1) * width * 4, -1, - width_byte_4))
+
+    def png_pack(png_tag, data):
+        chunk_head = png_tag + data
+        return struct.pack("!I", len(data)) + chunk_head + struct.pack("!I", 0xFFFFFFFF & zlib.crc32(chunk_head))
+
+    data = b"".join([
+        b'\x89PNG\r\n\x1a\n',
+        png_pack(b'IHDR', struct.pack("!2I5B", width, height, 8, 6, 0, 0, 0)),
+        png_pack(b'IDAT', zlib.compress(raw_data, 9)),
+        png_pack(b'IEND', b'')])
+
+    with open(path, 'wb') as f:
+        f.write(data)
+        return True
+