def _convert_image(self, file_path: str, preview_dims: ImgDims) -> Image:
"""
refer: https://legacy.imagemagick.org/Usage/thumbnails/
like cmd: convert -layers merge -background white -thumbnail widthxheight \
-auto-orient -quality 85 -interlace plane input.jpeg output.jpeg
"""
img = Image(filename=file_path)
resize_dim = compute_resize_dims(dims_in=ImgDims(width=img.width,
height=img.height),
dims_out=preview_dims)
img.auto_orient()
img.iterator_reset()
img.background_color = Color("white")
img.merge_layers("merge")
if self.progressive:
img.interlace_scheme = "plane"
img.compression_quality = self.quality
img.thumbnail(resize_dim.width, resize_dim.height)
return img
def orient_and_resize(image_filename):
resized_images = {}
img = Image(filename=image_filename)
img.auto_orient()
(w,h) = img.size
w = int(w)
h = int(h)
filename_base = image_filename
filename_base = filename_base.replace("/", "-")
filename_base = filename_base.replace(" ", "_")
with img.clone() as img_clone:
img_clone.resize(1280, int((1280.0/w)*h))
fname = "Resized/" + filename_base + "_1280.jpg"
resized_images['1280'] = fname
img_clone.save(filename=PREFIX_DIR + fname)
with img.clone() as img_clone:
img_clone.resize(640, int((640.0/w)*h))
fname = "Resized/" + filename_base + "_640.jpg"
resized_images['640'] = fname
img_clone.save(filename=PREFIX_DIR + fname)
with img.clone() as img_clone:
img_clone.resize(320, int((320.0/w)*h))
fname = "Resized/" + filename_base + "_320.jpg"
resized_images['320'] = fname
img_clone.save(filename=PREFIX_DIR + fname)
with img.clone() as img_clone:
img_clone.resize(160, int((160.0/w)*h))
fname = "Resized/" + filename_base + "_160.jpg"
resized_images['160'] = fname
img_clone.save(filename=PREFIX_DIR + fname)
img.close()
return ((w, h), resized_images)
def resize_image(path=None, blob=None, img=None, name=None,
fmt='jpeg', auto_orient=True, upscale=False):
"""A coroutine that resizes a single image multiple times
Note that the same image buffer is used across multiple operations so
operations should be ordered from highest-quality to lowest.
Parameters:
- path/blob/img: Source data (img is a Wand Image object)
- name: The name of the file (for logging purposes only)
- fmt: The image format of the resulting images (default: 'jpeg')
- auto_orient: Automatically orient image before processing (default: true)
- upscale: Upscale images to fit the desired resolution if they're too small
(default: False)
Receives a 4-tuple of (size, quality, square, fp)
- size: The image will be resized so that the longest edge is this many pixels.
If None the image will not be resized.
- quality: The JPEG quality level
- square: If true, the images will be cropped to square before being resized
- fp: A file-like object to write() the result into
"""
if sum([bool(path), bool(blob), bool(img)]) != 1:
raise ValueError("One of 'path', 'blob', or 'img' is required")
if path:
img = Image(filename=path)
elif blob:
img = Image(blob=blob)
with img:
# If there are multiple frames only use the first one (this
# prevents GIFs and ICOs from exploding their frames into
# individual images)
if img.sequence:
for _ in range(1, len(img.sequence)):
img.sequence.pop()
# Rotation and conversion to desired output format
if auto_orient:
img.auto_orient()
img.format = fmt
while True:
size, quality, square, fp = yield
__log__.debug("[resizing] %s -> %s%s",
name or "<img data>",
"{}px".format(size) if size else "fullsize",
", square" if square else ""
)
if square:
crop = min(img.size)
img.crop(width=crop, height=crop, gravity='center')
if size is not None and (upscale or size < crop):
img.resize(size, size)
elif size is not None:
# Work around a bug in Wand's image transformation by
# manually calculating the scaled dimensions and resizing
ratio = size/max(img.size)
if upscale or ratio < 1:
img.resize(*[round(x*ratio) for x in img.size])
img.compression_quality = quality
try:
img.save(file=fp)
except IOError as e:
__log__.error("[error] Failed to write image: %s", e, exc_info=True)
raise
