ios - Overlay blend mode formula? -

-

i have 2 colors: 1 dynamically set , that's white 0.5 alpha. want calculate resulting white color if drawn on top of dynamic color using overlay blend mode.

i'm aware overlay combines multiply , screen blend modes.

multiply blend mode's formula is:

result color = (top color) * (bottom color) /255

while screen blend mode's is:

result color = 255 - [((255 - top color)*(255 - bottom color))/255]

how calculate resulting color overlay blend mode?

is there uicolor extension class out there out of box?

there 2 part of formula:

first part: if lower layer value > 127.5, following -

value unit = (255-lower layer value)/127.5

min value = lower layer value - (255-lower layer value)

overlay = (upper layer value * value unit) + min value

second part: if lower layer value < 127.5, following -

value unit=lower layer value/127.5

overlay = upper layer value * value unit

from formual can see final result depend on upper layer value. if upper layer value higher(lighter), final result more lighter.

from here.


Comments

Post a Comment

Popular posts from this blog

objective c - Change font of selected text in UITextView -

-
can suggest me how change font of selected text in uitextview.i cannot use uiwebview since have edit text. have seen pages app.how possible in app. see formatting text within uilabel differently . since need editing, should @ javascript-based editors such ckeditor or tinymce . highly recommend wwdc 2011 video session 511: "rich text editing in safari on ios."
Read more

php - Accessing POST data in Facebook cavas app -

-
so i've got simple form in canvas / iframe facebook app, , i'm trying pass along values post. reading on s.o. , fb's latest docs, understand it, data send via post form can accessed on receiving end $_request object. i read on thread on s.o. in order post forms work need pass along input named "signed_request" value current signed_request (i have signed request working ok otherwise...all login , authentication stuff working fine). isnt mentioned anywhere in official fb docs. so problem comes in $_request object signed request, , bunch of other session stuff. form inputs found. the way can read them set method of form "request" isn't real form method. takes of inputs , sends them args in url. horrible. here's sample page canvas app form i'm using try debug (leaving out authentication stuff): <form enctype="application/x-www-form-urlencoded" method="post" target="_top" id="my_form" action=...
Read more

c# - Getting control value when switching a view as part of a multiview -

-
i have following code in aspx page: <asp:button id="display_button" runat="server" text="display" onclick="button1_click" /> &nbsp; <asp:button id="edit_button" runat="server" text="edit" onclick="button2_click" /> &nbsp; <asp:button id="save_button" runat="server" text="save" onclick="button3_click" visible="false" /> &nbsp; <asp:multiview id="multiview1" runat="server" activeviewindex="0"> <asp:view id="view1" runat="server"> <asp:formview id="view_program" runat="server"> <itemtemplate> <%# eval("status").tostring().trim() %> </itemtemplate> </asp:formview> </asp:view> <asp:view id="view2" runat="server"> ...
Read more