Algorithms

13-Sep-07 0:28

for a component we are using we need a color to be converted to a hex number (this is no problem my college wrote the code for it) but now we need that number (wich is stored in a sql db) to be converted back to a color (for displaying purposes)
this is the code to convert a color to number:

Dim R As Byte = &HFF - color.R
        Dim G As Byte = &HFF - color.G
        Dim B As Byte = &HFF - color.B
        Dim co, cn As Integer
        co = R + 256 * G + 256 * 256 * B
        cn = &HFFFFFF - co

        Return cn

anyone know how I can 'revert' this conversion so that I get the color back

If my help was helpfull let me know, if not let me know why.

The only way we learn is by making mistaks.

Luc Pattyn13-Sep-07 1:36

13-Sep-07 1:36

have a look at Color.FromArgb()

TDDragon wrote:
The only way we learn is by making mistaks

You can also learn from reading documentation.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

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Tom Deketelaere13-Sep-07 1:43

13-Sep-07 1:43

Luc Pattyn wrote:
have a look at Color.FromArgb()

that was the first thing I tried but it doesn't return the correct color

If my help was helpfull let me know, if not let me know why.

The only way we learn is by making mistaks.

Luc Pattyn13-Sep-07 2:00

13-Sep-07 2:00

TDDragon wrote:
it doesn't return the correct color

if you create a Color from its RGB components (within their valid range) and then extract
its components again, you get the same RGB values you started with. This proves nothing
is wrong with FromArgb().

If it does not work for you, you did something wrong elsewhere. Why does your code invert the
color components (0xFF-...)? Did you forget to invert them a second time?

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

Tom Deketelaere13-Sep-07 2:13

13-Sep-07 2:13

well we are working with a component (datawindows) and in order to get that component to display the same color as was picked in .NET we need to convert them (that is what the above code does).
But now I have to display the color that has been saved to the db (in this converted state) in .NET. And that is where I'm stuck.
The problem is that I can't get the RGB and A extracted back from the converted integer
maybe an example would help

I used the color red for this one:

color.toargb(color.red) = -65536

put red true the conversion for the component and we get: 255
conversion: (255-255)+(256*(255-0))+(256*256*(255-0)) = 16776960
16777215-16776960=255

now getting the number in bold back isn't a problem the problem is that I don't know how to get R,G and B back from the above formula.

once I have these it's indeed a simply putting them thru the fromargb methode

hope this clears things up a bit

If my help was helpfull let me know, if not let me know why.

The only way we learn is by making mistaks.

Luc Pattyn13-Sep-07 2:36

13-Sep-07 2:36

I am using C# syntax here:

So what you are saying is you have a hex integer c=0x00bbggrr where rr,gg,bb are the
255-complement of R,G,B and you need to figure out the values for R, G and B?

int r=c%255;
int b=(c>>8)%255;
int g=(c>>16)%255;
Color col=Color.FromArgb(255-r,255-g,255-b);

BTW there is no need for magic constants such as 16777215 (which is 0x00FFFFFF)

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

Tom Deketelaere13-Sep-07 3:08

13-Sep-07 3:08

somehow that doesn't work I think that this line of code (from the conversion) is the cause off all this trouble:

co = R + 256 * G + 256 * 256 * B

if I use you're code I keep getting 0-values for R,G,B nomatter wich color I'm using Confused | :confused:

Luc Pattyn wrote:
BTW there is no need for magic constants such as 16777215 (which is 0x00FFFFFF)

I know

but on paper it's easier to look at the number Poke tongue | ;-P

to make it easier to read here is the entire code again

Dim R As Byte = &HFF - color.R
        Dim G As Byte = &HFF - color.G
        Dim B As Byte = &HFF - color.B
        Dim co, cn As Integer
        co = R + 256 * G + 256 * 256 * B
        cn = &HFFFFFF - co

        Return cn

'cn' is the value stored in the db and also the value that needs to be converted back to a color

If my help was helpfull let me know, if not let me know why.

The only way we learn is by making mistaks.

Luc Pattyn13-Sep-07 3:18

13-Sep-07 3:18

if something does not work properly, you need to debug it, which means test a simple
case and look at intermediate values to find out where exactly it starts to go wrong,
then fix that.

Luc Pattyn [Forum Guidelines] [My Articles]

Tom Deketelaere13-Sep-07 3:26

13-Sep-07 3:26

done that, still can't figure it out. Anyway I discused the problem with my boss and we'll just add a column to the db with the arg (vb.net style) value in it and use that one so my problem has been solved well at least worked around it Poke tongue | ;-P

thank you for you're time

If my help was helpfull let me know, if not let me know why.

The only way we learn is by making mistaks.

Tim Craig13-Sep-07 18:21

Tim Craig

13-Sep-07 18:21

TDDragon wrote:

<br />
Dim G As Byte = &HFF - color.G        <br />
Dim B As Byte = &HFF - color.B        <br />
Dim co, cn As Integer        <br />
co = R + 256 * G + 256 * 256 * B<br />

I'm not sure about the promotion rules in VB (that ugly stuff is VB? Unsure | :~

) But in C and C++ by declaring R, G, and B as "byte" the arithmetic on the right of "co = " would be performed as byte and then promoted to int to be stored in co. If that is the case, you're getting overflow and wrap around.

Save an endangered species. The American Engineer.

Tom Deketelaere13-Sep-07 20:46

13-Sep-07 20:46

didn't think of that but just tested it and there doesn't seem to be a problem with it (calculated it manualy (yes I still know how to do that Laugh | :laugh:

)) and compared it to what is storred in co and in cn
anyway we solved our problem by just storing the argb value of the color into the db in a new column (it's a work around but it works so... (this isn't something we wanted to loose time over))

thank you anyway

If my help was helpfull let me know, if not let me know why.

The only way we learn is by making mistaks.

Dinamyc priority asignation

Jeremy Falcon25-Sep-07 8:45

Jeremy Falcon

25-Sep-07 8:45

TDDragon wrote:
anyone know how I can 'revert' this conversion so that I get the color back

Speaking in VB because that's what you have...

Function GetRValue(ByVal nColor As Long) As Long
	GetRValue = nColor And &HFF&
End Function

Function GetGValue(ByVal nColor As Long) As Long
	GetGValue = (nColor \ &H100&) And &HFF&
End Function

Function GetBValue(ByVal nColor As Long) As Long
	GetBValue = (nColor \ &H10000) And &HFF&
End Function

Jeremy Falcon
Oatmeal, It's What's for Dinner.[^]

Nelek12-Sep-07 4:18

12-Sep-07 4:18

Hi all,

last days I'm trying to stablish a priority dinamically. The objective is to determine which object is the best option to be chosen every cycle execution, and then operate with it.

The objects are mashines. Some parameters (like consumed energy) affect directly the priority, others (like reaction time, non stop activity time...) affect inversely Proportional, other parameters have to have some fixed values (like steps in the process) and other are bool (like permission).

I have it more or less clear with the factors that have to go multiplying, dividing and so on... but I don't find any formule that gives me a desirable result.

More or less is something like:

Permission * Already_Activate * ((Energy / (Reaction_time * Non_Stop_Time)) + StepValue [Actual]).

This is a simplified example (actually I have 10 different parameters, some of them variable during the process), I hope you can understand what I mean.

Does anyone know any web where the creation of formules for dinamically calculate priorities or parameters is explained?

Or give me some tips, methodes to find it out by myself.

Thanks

Greetings.

--------
M.D.V.

If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?

Russell^'13-Sep-07 6:54

13-Sep-07 6:54

Nelek wrote:
dinamically

We understand your formula...but I can't understand how you wan't to 'dinamically' change the parameters.

You have:

priority=f(par1, par2, par3,...,parN);

where f mixes that parameters with '*' or '+' . This depends only on the logic of that parameter and only you can prepare f(...).

Now, if I well understand you want to change the output of the function f(...) (ie the priority) using the same parameters. This means that you need some extra parameters (we can call they as calibration-parameters): calib1, calib2...calibM. In this case:

priority=g(par1, par2, par3,...,parN, calib1, calib2...calibM);

The function g is more complex from f (you can for example implement it as a FIR/IIR filter).
The problem now is how change the calibration-parameters calib* (par* are constants).
Then you need a calibration step. This to learn how set calib* values.

It is not looking very very simple Unsure | :~

... but at the same time, not so hard

Russell

Nelek13-Sep-07 22:52

13-Sep-07 22:52

First of all, thanks for your answer. I know that is quite extrange, maybe with a little more info...

The fact is that the parameters won't change, I mean... they will be always the same parameters on the formule, but their value (at least in 70% of the parameters DO will change with the time).

Some of the parameters will have a constant value in every mashine, but others will change their value depending on the moment in which they are used. For example (taking the same parameters as above)

Permission can be 0 or 1 depending of the user that comand the mashine, if he wants the mashine to be available to interact with my program or not, or in some critical parts of the process where they have to work at 100% independantly of what happens around.

Already_Activate can be 0 or 1, this parameter will be set/reset by my programm.

Energy depends on the concrete mashine, from one mashine to another may be different, but always constant for every mashine.

Reaction_time is mashine dependant, like the energy. Is the time between my command and the answer to that command.

Non_Stop_Time is variable for every case, it is the time between the last time that the mashine had a command from my programm to the actual moment.

StepValue [Actual] can be variable with the time, but according to a relation of fixed values (the array). In some minutes will have a value, in other moments another value and so on.

Because of that the output of the function will be variable with the time. And this value (priority) is the value that I will check in a for every certain periode of time to choose the mashine that has to receive my commands or specifications. The higher the priority is, has more oportunities to be selected.

The concrete problem is that the formule I have to create should take care of all the parameters with fixed value, the actual moment and the values of the parameters that change with the time.

Trying to write similar to your answer I need a function more o less like that:

Priority = F (par1, par2, ..., parN, f1(t), f2(t), ... fN(t));

I already know (more o less) where the parameters have to be placed (numerator, denominator), but my problem is to connect the terms. I mean... for example:
the boolean values are to allow, discard some terms, because of that are out to multiply the term: Permision * (....) would be like: if (!Permision) {continue;} in the first line of a while (...) or a for (...), but...

I don't know if it's better to use only one fraction and add, substract, multiply... the terms of numerator/denominator. If it's better to use more fractions adding every partial result... If it's better to use only multiplications and divisions and then normalize to a fixed interval... Confused | :confused:

I would like to have a priority with a similar value with mashines of similar properties, but the tests that I have made give me results that I don't like (differences to big between very similar cases, or too small with very different cases... things like that) Mad | :mad:

It is the first time I have to do something like this. Im not bad with the algorithms, but this is killing me Dead | X|

Is there any procedure to reach such a thing? or is just empiric with tests and failures?

Greetings.

--------
M.D.V.

If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?

Help me to understand what I'm saying, and I'll explain it better to you

Wink | ;)

Russell^'14-Sep-07 0:02

14-Sep-07 0:02

I'm quite sure that to solve this problem you have to solve it in 2 steps:

Step 1:

Nelek wrote:
Permission can be 0 or 1 depending of the user that comand the mashine, if he wants the mashine to be available to interact with my program or not, or in some critical parts of the process where they have to work at 100% independantly of what happens around.

Already_Activate can be 0 or 1, this parameter will be set/reset by my programm.

Energy depends on the concrete mashine, from one mashine to another may be different, but always constant for every mashine.

Reaction_time is mashine dependant, like the energy. Is the time between my command and the answer to that command.

Non_Stop_Time is variable for every case, it is the time between the last time that the mashine had a command from my programm to the actual moment.

StepValue [Actual] can be variable with the time, but according to a relation of fixed values (the array). In some minutes will have a value, in other moments another value and so on.

There are what we called Parm1, ... parmN (parm*)

Now fix a 'standard' output:

priority_Std=F_std(parm1, parm2, ...parmN);

This step is quite simple, you gave good ideas on how mix this parameters to obtain the right output. The only problem is to choose the 'standard' output that you want to obtain (priority_Std).
I think that it could be the more probable output..

Step 2)

You will have

priority=priority_std+F_Variation(parm1, parm2, ...parmN, calib1, ...calibM);

M!=N in general (I hope that M<N)

where calib* is the calibration parameter at that time (you correcly refer this to a function of time), this mens that priority is a function of time. The parameters parm* mest be taken as constants.

Write the function F_std is quite simple...not the same for F_Variation!

One way is this

F_Variation=SumOn(i,j)(parm_i*parm_j*calib(i,j))

Now you have simply to find this calib values according on what priority_variation you want in different conditions.
Smile | :)

Russell

Nelek14-Sep-07 0:51

14-Sep-07 0:51

I have to read it slowly because I don't get correctly what you mean (I'm not english speaker), but I think I have an aproximated idea.

Thanks a lot for your help. I didn't thought about doing it in two steps. I was combining all in only one step and that was to become crazy Wink | ;)

:P

P.S. how about your template?

Russell^'14-Sep-07 1:07

14-Sep-07 1:07

think also to this
parm(N+1)=time
in step 1 it values 0, so it comes only in the second step.

Nelek wrote:

P.S. how about your template?

not well

The compiler doesn't match well my specialization member function with the general declaration.
Give me 2 or 3 days to find the way to tell him that they are the same thing;)
thanks Big Grin | :-D

Russell

Nelek14-Sep-07 1:51

14-Sep-07 1:51

To have value 0 in the step 1, shouldn't it be "parm (N - 1) = time"?????

Russell^'14-Sep-07 2:17

14-Sep-07 2:17

Sorry, probally I was not clear:

In the first step use only parm1, parm2, ... parmN.
where N is the number of parameters that you are talking about in the first post.

In the step 2 use:
parm1, parm2, ... parmN, and parmN+1 (i.e. the time)

put everithing here

F_Variation=SumOn(i,j)[parm_i*parm_j*calib(i,j)]

and now you have only to find the right values ot the calib matrix (it will be (N+1)x(N+1) ).

To solve it a possible way is to minimize the RMS method (mean squared error).

Russell

Nelek25-Sep-07 2:17