osx - Objective-C/Mac - Set Pixel Colour? -


in mac application, letting user paint on grid, each square on grid representing pixel , having own colour. possible take colour , simple 1 one produce image setting pixel colour?

i can't think of how else this. need export image once user has painted grid making.

thanks.

the aim of app: user can paint grid. final image might 16x16 pixels in size, user in app can paint each pixel square of grid (16x16). outputted format of final image might 16x16 pixels, literally on screen. while grid visually while painting larger. each square on grid represents pixel in final image, , user can put single colour each square. makes sense, if not shall try , elaborate , link example.

[tldr: use model-view-controller.]

there 3 distinct things consider here:

  1. the "ideal" image user drawing, grid of 16x16 (or many) coloured pixels.
  2. the onscreen representation of it, each pixel displayed @ larger size user interact with.
  3. an eventual image file exported app.

keeping elements separate in mind , implementation make life lot easier.

#1 model, , in case consist of array of 256 (or many) colour values, along descriptive data pixel dimensions , colour space. simple might not want create separate model class (although should), if it's array ivar sitting in monolithic app class should still think of distinct entity in own right.

#2 view (with controller tendencies), , should implement using custom nsview subclass. possible build grid of 256 instances of nscolorwell or other existing nsview type, silly. view has 2 jobs:

  1. draw model onscreen. iterating on data values , drawing each 1 filled rectangle of appropriate size. methods of nsbezierpath friends here, class methods fillrect , strokerect.
  2. mediate user input. example, might decide user colours pixel clicking on mouse. view sent event each mouse click, , need respond mapping click location correct pixel (basically matter of division) , making appropriate changes model.

#3 in ways kind of view, in way of representing model. code producing included model (say if there's 1 canonical way of serialising data), it's practice put somewhere else, if might want add other arbitrary mechanisms later.

the key here image nothing nsview side of things, it's matter of taking model data , writing out. can writing via nsimage methods or via core graphics, mentioned in other answers, absolutely shouldn't try manhandle directly off screen. way lies madness!


Comments

Post a Comment

Popular posts from this blog

c++ - Is it possible to compile a VST on linux? -

for class project i'm attempting write vst plugin backed cuda. current cuda workflow on linux box, i'd prefer compile , link there. according wikipedia , should possible (i couldn't find steinberg documentation relevant linux) can't find makefile or instructions on how build if aren't using xcode or visual studio. i'm vst 3 sdk doesn't support linux. when try compile plugin under linux, error: ./base/source/fatomic.cpp:39:30: fatal error: libkern/osatomic.h: no such file or directory this issue caused following code in "vst3 sdk/base/source/fatomic.cpp" #if mac #include <libkern/osatomic.h> #if mac_os_x_version_min_required > mac_os_x_version_10_4 #define native_atomic_type (volatile int32_t*) #else #define native_atomic_type (int32_t*) #endif #elif windows #include <windows.h> #endif but hope compiling under linux work vst sdk 2.4. reading. jvstwrapper seems run on lin...
Read more

java - Output of Eclipse is rubbish -

i want write program in eclipse language different english. when display output using system.out program, displays output correctly in console editor. when accept input console , output it, output rubbish. how can solve it. many thnaks i'm not sure if problem, have character encoding problem. make sure you're using unicode, utf-8. you can read more @ official docs converting non-unicode text .
Read more

jquery - Confused with JSON data and normal data in Django ajax request -

i read json internet still have not got grasp of it. reading article http://webcloud.se/log/ajax-in-django-with-jquery/ i not understood first part function using json def xhr_test(request, format): if request.is_ajax(): if format == 'xml': mimetype = 'application/xml' if format == 'json': mimetype = 'application/javascript' data = serializers.serialize(format, examplemodel.objects.all()) return httpresponse(data,mimetype) # if want prevent non xhr calls else: return httpresponse(status=400) my main problems are from function getting format variable does format json mean data given function json or data recived json can give me simple example ouput of function data = serializers.serialize(format, examplemodel.objects.all()) how use data when response in jquery function if don't use json in above function how input , response chnage thanks ...
Read more