C / C++ / MFC

Re: conversion from double datatype to pixel in VC++

20-Mar-07 0:49

kindd wrote:
so suggest what should i do to draw in pixels.

Using This[^] ?

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kindd20-Mar-07 1:00

kindd

20-Mar-07 1:00

nill

Spam police

toxcct20-Mar-07 1:11

Re: conversion from double datatype to pixel in VC++

20-Mar-07 1:11

please delete this post, i already saw your answer and replied to you

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David Crow20-Mar-07 3:38

David Crow

20-Mar-07 3:38

toxcct wrote:
there's nothing logical in having floating point data types to store integers (moreover, such data types may loose the integers precision)...

This sounds backwards. Floating point data types have more precision than integers so what exactly is being lost?

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

Re: conversion from double datatype to pixel in VC++

toxcct20-Mar-07 3:48

Re: conversion from double datatype to pixel in VC++

20-Mar-07 3:48

due to how floating point manage their memory, they don't store exact values but approximations.
they can store larger numbers, but with less precision... knowing this, that's normal to encounter a 1.9999999999999 in a float we actually assigned a 2
i can't find the exact link to what i affirm, but i hope some here understand what i mean and can provide a relevant link.

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David Crow20-Mar-07 5:13

David Crow

20-Mar-07 5:13

I see what you are saying, and I was thinking of something completely different. Yes, I'm familiar with floating-point issues (storage vs. usage). That aside, it just seems silly to store "pixel" numbers in a floating-point variable. They're never going to be anything but whole.

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

passing 4 parameters in SendMessage()

sulabh_expert@rediffmail.com19-Mar-07 21:02

19-Mar-07 21:02

Hi all,

My problem is i want to pass 4 variables in my SendMessage function.
What i am doing is pasing a single variable and the other three through structure like this :-

struct pasiin_val
{
int index;
CString url;
CString task_n;
};

void CMyThread::LogMessage(CString& logmsg)
{
if (m_pLogWnd)
{
pasiin_val obj_val;
obj_val.index = test_int;
obj_val.url = test_str;
obj_val.task_n = test_task_name;
m_pLogWnd->SendMessage(LOGMSG, (WPARAM)(CString*)&logmsg, obj_val);

}
}

when i am trying to do this its giving an error:-

error C2664: 'SendMessageA' : cannot convert parameter 3 from 'struct pasiin_val' to 'long'

can anybody help me in this......

thanks in advance

prasad_som19-Mar-07 21:05

prasad_som

19-Mar-07 21:05

sulabh_expert@rediffmail.com wrote:
m_pLogWnd->SendMessage(LOGMSG, (WPARAM)(CString*)&logmsg, obj_val);

Modify this to,

m_pLogWnd->SendMessage(LOGMSG, (WPARAM)(&logmsg),(LPARAM)(&obj_val));

Prasad
Notifier using ATL | Operator new[],delete[][^]

sulabh_expert@rediffmail.com19-Mar-07 21:10

Re: passing 4 parameters in SendMessage() [modified]

19-Mar-07 21:10

now there is no error

But when i m accessing it my MessageMap function like this:-

recv_val *obj_recv = static_cast<recv_val*>(lparam);

its giving an error:-

error C2440: 'static_cast' : cannot convert from 'long' to 'struct recv_val *'

recv val is also a structure in other class in which i m having my messagemap

struct recv_val
{
CString Recv_URL;
CString Recv_name;
int Recv_index;
};

prasad_som19-Mar-07 21:15

prasad_som

19-Mar-07 21:15

sulabh_expert@rediffmail.com wrote:
recv_val *obj_recv = static_cast(lparam);

See replies below.

-- modified at 3:29 Tuesday 20th March, 2007

Prasad
Notifier using ATL | Operator new[],delete[][^]

sulabh_expert@rediffmail.com19-Mar-07 21:18

19-Mar-07 21:18

same error is coming..........

prasad_som19-Mar-07 21:25

prasad_som

19-Mar-07 21:25

Use reinterpret_cast.

recv_val *obj_recv = reinterpret_cast<recv_val*>(lParam);

Prasad
Notifier using ATL | Operator new[],delete[][^]

toxcct19-Mar-07 21:25

19-Mar-07 21:25

use reinterpret_cast<>() instead

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Parthi_Appu19-Mar-07 21:20

Parthi_Appu

19-Mar-07 21:20

sulabh_expert@rediffmail.com wrote:
struct recv_val
{
CString Recv_URL;
CString Recv_name;
int Recv_index;
};

Make sure the struct is properly defined. In the sender side you defined as int, CString, CString...

You can typecaste as below,

struct recv_val* pStruct = (recv_val*)(LPVOID)lParam;

Do your Duty and Don't expect the Result

toxcct19-Mar-07 21:24

19-Mar-07 21:24

using C style cast is the simplicity mistake...;P

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sulabh_expert@rediffmail.com19-Mar-07 21:28

19-Mar-07 21:28

thanku all my problem got solved.................. Smile | :)

Divyang Mithaiwala21-Apr-10 3:07

Divyang Mithaiwala

21-Apr-10 3:07

I am facing same issue.
My message received at other side but I can access/cast structure at receiving side.
Can you specify which one solution works for you?

regards,
Divyang Mithaiwala

David Crow20-Mar-07 3:40

David Crow

20-Mar-07 3:40

sulabh_expert@rediffmail.com wrote:
recv val is also a structure in other class in which i m having my messagemap

struct recv_val
{
CString Recv_URL;
CString Recv_name;
int Recv_index;
};

The structures must match. Roll eyes | :rolleyes:

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb