How to convert image to GIF with only two color index in Imagick -

-

i want convert image gif format 2 color, black , white

so every pixel in output image black or white

does know way convert in imagick ?

although final conversion write out two-color gif same, there subtly different ways of converting image 2 color black , white.

here methods below:

helper method force images pixels of values 0,0,0 , 255,255,255

function forceblackandwhite(imagick $imagick, $dithermethod = \imagick::dithermethod_no) {     $palette = new imagick();     $palette->newpseudoimage(1, 2, 'gradient:black-white');     $palette->setimageformat('png');     //$palette->writeimage('palette.png');      // make image use these palette colors     $imagick->remapimage($palette, $dithermethod);     $imagick->setimagedepth(1); }

just use remap palette force image 2 colors without dithering.

function twocolorpaletteonly() {     $imagick = new imagick(__dir__."/../images/biter_500.jpg");     forceblackandwhite($imagick, \imagick::dithermethod_no);     $imagick->setimageformat('gif');     $imagick->writeimage("./outputpalette.gif"); }

palette output:

enter image description here

using http://phpimagick.com/imagick/posterizeimage allows different control on dithering process.

function twocolorviaposterize() {     $imagick = new imagick(__dir__."/../images/biter_500.jpg");     $imagick->transformimagecolorspace(\imagick::colorspace_gray);     $imagick->posterizeimage(2, \imagick::dithermethod_riemersma);     forceblackandwhite($imagick);     $imagick->setimageformat('gif');     $imagick->writeimage("./outputposterize.gif"); }

posterize output:

enter image description here

the thresholdimage function allows control @ @ 'level' image changes black white.

function twocolorviathreshold() {     $imagick = new imagick(__dir__."/../images/biter_500.jpg");     $imagick->transformimagecolorspace(\imagick::colorspace_gray);     $imagick->thresholdimage(0.5 * \imagick::getquantum());     forceblackandwhite($imagick);     $imagick->setimageformat('gif');     $imagick->writeimage("./outputthreshold.gif");  }

threshold output:

enter image description here

using blackthresholdimage , whitethresholdimage functions allows control color threshold per channel

function twocolorviacolorthreshold() {     $imagick = new imagick(__dir__."/../images/biter_500.jpg");     $thresholdcolor = "rgb(127, 100, 100)";     $imagick->blackthresholdimage($thresholdcolor);     $imagick->whitethresholdimage($thresholdcolor);     forceblackandwhite($imagick);     $imagick->setimageformat('gif');     $imagick->writeimage("./outputcolorthreshold.gif"); }

colorthreshold output

enter image description here

extracting single image channel can produce 'cleaner' looking output image.

function twocolorviacolorchannelthreshold() {     $imagick = new imagick(__dir__."/../images/biter_500.jpg");     $imagick->separateimagechannel(\imagick::channel_red);     $imagick->thresholdimage(0.5 * \imagick::getquantum());     forceblackandwhite($imagick);     $imagick->setimageformat('gif');     $imagick->writeimage("./outputcolorchannelthreshold.gif"); }

colorchannelthreshold

enter image description here

we can combine rgb channels more precisely using colormatriximage function, gives complete control on how separate r g b values should affect output image.

function twocolorviacolormatrixchannelthreshold() {     $imagick = new imagick(__dir__."/../images/biter_500.jpg");       //      $colormatrix = [         0.6, 0.2, 0.2, 0.0, 0.0,         0.0, 0.0, 0.0, 0.0, 0.0,         0.0, 0.0, 0.0, 0.0, 0.0,         0.0, 0.0, 0.0, 1.0, 0.0,         0.0, 0.0, 0.0, 0.0, 0.0,     ];      // intensity of red channel after applying color matrix takes     // values pixels before transformation of:     // 60% of red, 20% blue, 20% green     $imagick->colormatriximage($colormatrix);     $imagick->separateimagechannel(\imagick::channel_red);     $imagick->thresholdimage(0.5 * \imagick::getquantum());     forceblackandwhite($imagick);     $imagick->setimageformat('gif');     $imagick->writeimage("./outputcolormatrixchannelthreshold.gif"); }

colormatrixchannelthreshold output

enter image description here

the output images code above are:


Comments

Post a Comment

Popular posts from this blog

Load Balancing in Bluemix using custom domain and DNS SRV records -

-
i'm trying load balancing of application in bluemix using custom domain , srv record in dns manager. created own doamin ccbluemix.dynu.com , added custom domain bluemix. created application in region , created route custom domain myapp.ccbluemix.dynu.com deployed same application in uk region , created route custom domain myapp.ccbluemix.dynu.com there well. now whenever user hits route want load balancing between , uk region alternate requests served , uk regions. for created srv records like _http._tcp.ccbluemix.dynu.com srv eu-gb.mybluemix.net [priority: 0] [weight: 50] 10 _http._tcp.ccbluemix.dynu.com srv mybluemix.net [priority: 0] [weight: 50] 10 but nothing happening , i'm not able access application using custom route @ all. if create 'a' record cc-load-bal-app.ccbluemix.dynu.com 75.126.81.68 i can access app using custom route ends hitting server. how can achieve load balancing using srv records? wrong creating srv records here? i read ne...
Read more

oracle - pls-00402 alias required in select list of cursor to avoid duplicate column names -

-
my cursor : select xzis.msisdn msisdn, xzis.in_account_number in_account_number xxobw_zte_in_sync xzis not exists (select 1 hz_contact_points hcp, hz_cust_accounts hca hcp.owner_table_id = hca.party_id , hcp.owner_table_name = 'hz_parties' , hcp.phone_number = substr (xzis.msisdn, -8) , nvl (hca.attribute12, 'nil') = xzis.in_account_number); i have given alias columns, still facing issue. suggestions? it's cursor. 1 has no such problems. problem is, when you're joining 2 tables, or apply wrong aliases in subselect, cursor may @ end return 2 columns same name/alias. the problem not need alias, no 2 columns can have same alias (the name counting alias, when no alias given). apparently has happened, far can tell, it's ...
Read more

python - Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] error -

-
Image
i getting same error when python manage.py runserver. there no such error when have ubuntu 15.10. got started when upgraded ubuntu 16.04. question might duplicate have tried solution provided question have applied command dpkg --configure -a, have done apt-get update,upgrade,dist-upgrade, clean, -f install. have reinstalled python2.7 , python3 no success though. here screenshot while trying run django application i got after re-installing python please me? bashrc file # ~/.bashrc: executed bash(1) non-login shells. # see /usr/share/doc/bash/examples/startup-files (in package bash-doc) # examples # if not running interactively, don't case $- in *i*) ;; *) return;; esac export pythonhome="/usr/bin/python" echo $virtualenvwrapper_python echo 'tushant' # don't put duplicate lines or lines starting space in history. # see bash(1) more options histcontrol=ignoreboth # append history file, don't overwrite shopt -s histappend # setting h...
Read more