Use chop before resize in Imagemagick

Question

I am using paperclip gem to process images.

In some images, I need to chop the top 35 pixels of the source image and then do the conversions and processing

Currently I am using

:convert_options => {
                                all: lambda{ |instance| "#{!instance.chop_top.blank? ? '-chop 0x35' : '' } -limit memory 64 -limit map 128"},
                                mobile_sm: "-resize 620 -quality 90 -strip -interlace Plane",
                                mobile_lg: "-resize 1280 -quality 80 -strip -interlace Plane",
                                feature: "-quality 90 -strip -interlace Plane",
                                 medium: "-quality 85 -strip -interlace Plane",
                                 preview: "-quality 85 -strip -interlace Plane", 
                                 tiny: "-quality 90 -strip -interlace Plane"}

This works, mostly, but on the mobile_lg it seems the chop occurs after resizing (and I guess this happens on the others as well, its just less visible)

How can I use -chop so it will do it before the resize?

Answer 1

solved it with +repage and not in :all

so essentially it looks like

all: "-limit memory 64 -limit map 128",
    mobile_sm: lambda{ |instance| "#{!instance.chop_top.blank? ? '-chop 0x31 +repage' : '' } -resize 640 -quality 90 -strip -interlace Plane"},
    mobile_lg: lambda{ |instance| "#{!instance.chop_top.blank? ? '-chop 0x31 +repage' : '' } -resize 1280 -quality 80 -strip -interlace Plane"},

it can be refactored, but c'est la vie

for some reason, putting the lambda in all doesn't work, so I guess the behavior for that is different.