Canvas draws pictures. For the effect of canvas.toDataURL ('image/png'), the img image is not clear, there are masks,

Why the picture from canvas.toDataURL () has no background, and the words on it are so shallow that they can hardly be seen.
something like this.

clipboard.png

clipboard.png

clipboard.png

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b2c322-33ea5.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b2c322-33ea5.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?