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

javascript - How to get current YouTube IDs via iMacros? -

-
i want viewed youtube video id , save csv via imacros, gets nothing. here js code: var videoid; videoid ="code:"; videoid +="url goto=https://www.youtube.com/watch?v=dbnywxdz_pa"+"\n"; videoid +="add !extract {{!urlcurrent}}"+"\n"; videoid +="set !var1 eval(\"var s=\"{{!urlcurrent}}\"; s.match((?<=watch\\?v=|/videos/|embed\\/)[^#\\&\\?]*);s[0]; \")"+"\n"; videoid +="add !extract {{!var1}}"+"\n"; videoid +="saveas type=extract folder=* file=url.csv"+"\n"; try this: var videoid = "url goto=https://www.youtube.com/watch?v=dbnywxdz_pa" + "\n"; videoid += "set !extract {{!urlcurrent}}" + "\n"; videoid += 'set !extract eval("\'{{!extract}}\'.match(/v=(.{11})/)[1];")' + "\n"; videoid += "saveas type=extract folder=* file=url.csv" + "\n"; iimplay
Read more

c# - Maintaining a program folder in program files out of date? -

-
for program i'm writing in vs c# wpf need store user related information on user's computer. far knew has been done creating folder in c:\program files , adding whatever program related info folder in subfolders or whatever. after doing browsing came across lot of people saying method out of date because access may denied create folder there, works administrative accounts, etc.. 1 site suggested saving c:\users\username\appdata\roaming or c:\users\username\appdata\local. question best , date method saving program data users computer? also take @ msdn article . it uwp apps have general idea put if developing wpf app. you may need these folders: environment.specialfolder.applicationdata environment.specialfolder.localapplicationdata environment.specialfolder.commonapplicationdata
Read more

emulation - Android map show my location didn't work -

-
i have been struggle current location in google map, tried official map demo, not working also. shows getmylocation button on upper right, didn't show blue dot on map current location. here code , i'm using emulator target api 23, guess may emulator's problem since code download directly github. advice appreciated. [screenshot][1] package com.example.mapdemo; import com.google.android.gms.maps.googlemap; import com.google.android.gms.maps.googlemap.onmylocationbuttonclicklistener; import com.google.android.gms.maps.onmapreadycallback; import com.google.android.gms.maps.supportmapfragment; import android.manifest; import android.content.pm.packagemanager; import android.os.bundle; import android.support.annotation.nonnull; import android.support.v4.app.activitycompat; import android.support.v4.content.contextcompat; import android.support.v7.app.appcompatactivity; import android.widget.toast; /** * demo
Read more