def image_to_data(img, compression_quality=95, fmt='JPEG', png_compression_level=9, jpeg_optimized=True, jpeg_progressive=False):
'''
Serialize image to bytestring in the specified format.
:param compression_quality: is for JPEG and goes from 0 to 100. 100 being lowest compression, highest image quality
:param png_compression_level: is for PNG and goes from 0-9. 9 being highest compression.
:param jpeg_optimized: Turns on the 'optimize' option for libjpeg which losslessly reduce file size
:param jpeg_progressive: Turns on the 'progressive scan' option for libjpeg which allows JPEG images to be downloaded in streaming fashion
'''
ba = QByteArray()
buf = QBuffer(ba)
buf.open(QBuffer.WriteOnly)
fmt = fmt.upper()
is_jpeg = fmt in ('JPG', 'JPEG')
w = QImageWriter(buf, fmt.encode('ascii'))
if is_jpeg:
if img.hasAlphaChannel():
img = blend_image(img)
# QImageWriter only gained the following options in Qt 5.5
if jpeg_optimized and hasattr(QImageWriter, 'setOptimizedWrite'):
w.setOptimizedWrite(True)
if jpeg_progressive and hasattr(QImageWriter, 'setProgressiveScanWrite'):
w.setProgressiveScanWrite(True)
w.setQuality(compression_quality)
elif fmt == 'PNG':
cl = min(9, max(0, png_compression_level))
w.setQuality(10 * (9-cl))
if not w.write(img):
raise ValueError('Failed to export image as ' + fmt + ' with error: ' + w.errorString())
return ba.data()
def image_to_data(img, compression_quality=95, fmt='JPEG', png_compression_level=9, jpeg_optimized=True, jpeg_progressive=False):
'''
Serialize image to bytestring in the specified format.
:param compression_quality: is for JPEG and goes from 0 to 100. 100 being lowest compression, highest image quality
:param png_compression_level: is for PNG and goes from 0-9. 9 being highest compression.
:param jpeg_optimized: Turns on the 'optimize' option for libjpeg which losslessly reduce file size
:param jpeg_progressive: Turns on the 'progressive scan' option for libjpeg which allows JPEG images to be downloaded in streaming fashion
'''
ba = QByteArray()
buf = QBuffer(ba)
buf.open(QBuffer.WriteOnly)
fmt = fmt.upper()
is_jpeg = fmt in ('JPG', 'JPEG')
w = QImageWriter(buf, fmt.encode('ascii'))
if is_jpeg:
if img.hasAlphaChannel():
img = blend_image(img)
# QImageWriter only gained the following options in Qt 5.5
if jpeg_optimized and hasattr(QImageWriter, 'setOptimizedWrite'):
w.setOptimizedWrite(True)
if jpeg_progressive and hasattr(QImageWriter, 'setProgressiveScanWrite'):
w.setProgressiveScanWrite(True)
w.setQuality(compression_quality)
elif fmt == 'PNG':
cl = min(9, max(0, png_compression_level))
w.setQuality(10 * (9-cl))
if not w.write(img):
raise ValueError('Failed to export image as ' + fmt + ' with error: ' + w.errorString())
return ba.data()
def image_to_data(
img, compression_quality=95, fmt="JPEG", png_compression_level=9, jpeg_optimized=True, jpeg_progressive=False
):
"""
Serialize image to bytestring in the specified format.
:param compression_quality: is for JPEG and goes from 0 to 100. 100 being lowest compression, highest image quality
:param png_compression_level: is for PNG and goes from 0-9. 9 being highest compression.
:param jpeg_optimized: Turns on the 'optimize' option for libjpeg which losslessly reduce file size
:param jpeg_progressive: Turns on the 'progressive scan' option for libjpeg which allows JPEG images to be downloaded in streaming fashion
"""
fmt = fmt.upper()
ba = QByteArray()
buf = QBuffer(ba)
buf.open(QBuffer.WriteOnly)
if fmt == "GIF":
w = QImageWriter(buf, b"PNG")
w.setQuality(90)
if not w.write(img):
raise ValueError("Failed to export image as " + fmt + " with error: " + w.errorString())
from PIL import Image
im = Image.open(BytesIO(ba.data()))
buf = BytesIO()
im.save(buf, "gif")
return buf.getvalue()
is_jpeg = fmt in ("JPG", "JPEG")
w = QImageWriter(buf, fmt.encode("ascii"))
if is_jpeg:
if img.hasAlphaChannel():
img = blend_image(img)
# QImageWriter only gained the following options in Qt 5.5
if jpeg_optimized and hasattr(QImageWriter, "setOptimizedWrite"):
w.setOptimizedWrite(True)
if jpeg_progressive and hasattr(QImageWriter, "setProgressiveScanWrite"):
w.setProgressiveScanWrite(True)
w.setQuality(compression_quality)
elif fmt == "PNG":
cl = min(9, max(0, png_compression_level))
w.setQuality(10 * (9 - cl))
if not w.write(img):
raise ValueError("Failed to export image as " + fmt + " with error: " + w.errorString())
return ba.data()
