[image processing] More image processing options [5.3.0-B1]

Currently the ImageHelper class we're using to process user-uploaded images offers several post processing options, like:

• resizing to given dimensions
• cropping, with piece to crop take from user-specified location (e.g. center, one of a corners, absolute margins)
• filling in black bars added during cropping with any color
• watermarking

However there is always a place for improvements. I'm proposing to add following options:

Examples

• <inp2:u_Field name="PrimaryImage" format="resize:800x600;orientation:auto"/> - will adjust resize dimensions based on source image orientation
• <inp2:u_Field name="PrimaryImage" format="resize:800x600;output_format:jpg"/> - will convert image to jpg preserving maximal image quality
• <inp2:u_Field name="PrimaryImage" format="resize:800x600;output_format:jpg;quality:70"/> - will convert image to jpg with 70% image quality (default setting in Photoshop when saving jpg files)
• <inp2:u_Field name="PrimaryImage" format="resize:800x600;quality:70"/> - will convert image, but will apply 70 number as-is to the quality parameter, which will result in broken png image (when png is uploaded)

Solution

Plan (part 1 - support for "quality" option)

1. in "ImageHelper::parseFormat" method parse "quality:X" format: - 0.5h
   • the "X" is a number between 0 and 100
   • when "X" happens to be something else throw an exception
   • the "$res" array would initially contain array('quality' => 100)
2. add protected "ImageHelper::convertQualityToCompression($quality)" method after "ImageHelper::ScaleImage" method that will: - 0.5h
   • subtract value from 100 (when 60 is given it will become 40)
   • divide by 10 and round it (the (100-65)/10 becomes 4)
   • return the result
3. in "ImageHelper::ScaleImage" method where "$write_function" is used to save file on disk: - 0.5h
   • where "0" is used now (the PNG files) use result of "ImageHelper::convertQualityToCompression" method on "quality" parameter parsed before
   • where "100" is used (everything else) use "quality" parameter parsed before

Plan (part 2 - support for "output_format" option):

1. in "ImageHelper::parseFormat" method parse "output_format:X" format: - 0.5h
   • the "X" is a string from this list: jpg, png, gif, bmp, auto
   • when "X" happens to be something else throw an exception
   • the "$res" array would initially contain array('output_format' => 'auto')
2. in "ImageHelper::ScaleImage" method: - 0.5h
   • after "$write_function" variable was defined create "$output_format_map" array, where:
     • key is value for "output_format" option, except "auto"
     • value is 2 last matching elements (also separated by colon) from $resize_map" array (e.g. "imagejpeg:jpg" value for "jpg" key and so on)
   • if "output_format" option isn't "auto", then change "$write_function" and "$file_extension" variables to values extracted from "$output_format_map" array based on used "output_format" option value

Plan (part 3 - support for "orientation" option):

1. in "ImageHelper::parseFormat" method parse "orientation:X" format: - 0.5h
   • the "X" is a string from this list: auto, manual, portrait, landscape
   • when "X" happens to be something else throw an exception
   • the "$res" array would initially contain array('orientation' => 'manual')
2. add protected "ImageHelper::shouldRotateDimensions($src_image, $dst_width, $dst_height, array $params)" method, that will: - 0.5h
   • store $params['orientation'] into $orientation variable
   • if $orientation is "manual", then return "false"
   • if $orientation is "auto", but only one of $dst_width/$dst_height is a number, then throw an exception
   • if $orientation is "auto", then set $resized_orientation variable to orientation ("portrait" or "landscape") based on $dst_width and $dst_height variable values
   • otherwise set $resized_orientation variable to value of $orientation variable (at this point it could be only "portrait" or "landscape")
   • get image dimensions of "$src_image" image using "\ImageHelper::getImageInfo" method
   • set $src_image_orientation variable to orientation ("portrait" or "landscape") of $src_image based on above retrieved image dimensions and store it into 
   • return true, when $src_image_orientation doesn't match $resized_orientation
   • return false otherwise
3. in "ImageHelper::ResizeImage" method, when "orientation" is "auto" AND we're inside if ( !$this->isSVG($src_image) && ($params['max_width'] > 0 || $params['max_height'] > 0) ) { logic branch (as 1st thing): - 0.5h
   • if "ImageHelper::shouldRotateDimensions" returns thrusy value, then:
     • swap "$params['max_width']" and "$params['max_height']" values
     • swap "$params['crop_x']" and "$params['crop_y']" values, but only when such keys exist

Quote: 4h*1.4 = 6h

Related Discussions

• Center crop without resize changes the image [5.2.2-B1]
• [uploader] Incorrect uploaded image extension, when "storage_format" is used [5.2.2-B1]
• [image processing] Add support for webp images [5.2.2-B2]

Related Tasks

INP-1668 - Getting issue details... STATUS

INP-1847 - Getting issue details... STATUS