C / C++ / MFC

16-Sep-09 3:18

Hi All

how to create new bitmap ?

~~~~~~~~~~~~~Raju~~~~~~~~~~~~~

Code-o-mat16-Sep-09 3:28

16-Sep-09 3:28

By selecting 'New' from the file menu.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Sometimes you just have to hate coding to do it well. <

Game-point16-Sep-09 3:31

16-Sep-09 3:31

~~~~~~~~~~~~~Raju~~~~~~~~~~~~~

Code-o-mat16-Sep-09 3:33

16-Sep-09 3:33

Please provide a bit more information about what you mean because otherwise we won't be able to help.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Sometimes you just have to hate coding to do it well. <

Game-point16-Sep-09 3:54

16-Sep-09 3:54

i have one image file which contains 5 buildings ..i want to cut and save only the 5th building ,other four buildings are not shown in the image.

but when we are save the image 5th building not shown other four buildings are shown in the image...

this is my code snippet::

<code>
	HDC pDC=::GetDC(0);
HDC TmpDC=CreateCompatibleDC(pDC);
CImage _image;
_image.Load(_T("//read.tif"));
int width=_image.GetWidth();
int height=_image.GetHeight();
HGDIOBJ TmpObj2 = SelectObject(TmpDC,(HGDIOBJ)(HBITMAP)_image);			
Rectangle(TmpDC, 0,0, width/2, height/2 );
SelectObject(TmpDC,TmpObj2);
_image.Save( _T("D:\\newy.jpg"), Gdiplus::ImageFormatBMP);
::ReleaseDC(NULL,pDC);

</code>

~~~~~~~~~~~~~Raju~~~~~~~~~~~~~

Code-o-mat16-Sep-09 4:16

16-Sep-09 4:16

So let me get this right, you open a tif file, draw a rectangle on it that is suposed to overlap some part of the picture and then you save the image to another file, right? (Btw why do you specify Gdiplus::ImageFormatBMP for the Save call while you are trying to save a jpg?) Your problem is that not the part of the image is overlapped you want? Why don't you move the rectangle then?

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Sometimes you just have to hate coding to do it well. <

Game-point16-Sep-09 4:22

16-Sep-09 4:22

how to create one rectangle piece of image from existing image??

this is doubt Confused | :confused:

~~~~~~~~~~~~~Raju~~~~~~~~~~~~~

Code-o-mat16-Sep-09 5:01

16-Sep-09 5:01

Ah well, create a new bitmap in memory with the required size, blit from the source image to the target image the part you want to cut out and then save this new bitmap.
So something like this:

HDC pDC=::GetDC(0);
HDC TmpDC=CreateCompatibleDC(pDC);
CImage _image;
_image.Load(_T("//read.tif"));
int width=_image.GetWidth();
int height=_image.GetHeight();
HGDIOBJ TmpObj2 = SelectObject(TmpDC,(HGDIOBJ)(HBITMAP)_image);			

int newWidth  = width/2;
int newHeight = height/2;
HDC NewDC = CreateCompatibleDC(TmpDC);
HBITMAP NewBitmap = CreateCompatibleBitmap(TmpDC, newWidth, newHeight);
HGDIOBJ NewTmpObj = SelectObject(NewDC, NewBitmap);

BitBlt(NewDC, 0, 0, newWidth, newHeight, TmpDC, 0, 0, SRCCOPY);

SelectObject(NewDC, NewTmpObj);
DeleteDC(NewDC);

SelectObject(TmpDC,TmpObj2);
::ReleaseDC(NULL,pDC);

CImage newImage;
newImage.Attach(NewBitmap);
newImage.Save( _T("D:\\newy.jpg"), Gdiplus::ImageFormatJPEG);
DeleteObject(NewBitmap); //Is this needed, will CImage destroy the bitmap or not?

I am not saying this code works or if it compiles at all, but it can be a starting point for you to get the idea, good luck.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Sometimes you just have to hate coding to do it well. <

Nuri Ismail16-Sep-09 5:02

Nuri Ismail

16-Sep-09 5:02

Hi,
I saw (from your posts) that you are using CImage class. So if you need to copy the loaded image to the new one you can use the BitBlt() method of CImage.

Here is the code fragment to create a copy of given original image:

// First load the original image
CImage imageOriginal;
imageOriginal.Load(_T("Here is the path to your original image"));

// Make a copy of the original image
CImage imageNew;
imageNew.Create(imageOriginal.GetWidth(), imageOriginal.GetHeight(), imageOriginal.GetBPP());
imageOriginal.BitBlt(imageNew.GetDC(), CPoint(0,0));
imageNew.ReleaseDC();

// Now imageNew holds the copy of original image
....

The above example makes an exact copy of the loaded image.

If you need to copy the specific part of the loaded image, for instance a rectangular part, then you can use the BitBlt() method again, but this time the code could be something like this:

// First load the original image
CImage imageOriginal;
imageOriginal.Load(_T("Here is the path to your original image"));

// Here is the rect that we will copy from the original image (in this case 1/4 of it)
CRect rectCopy(0, 0, imageOriginal.GetWidth() / 2, imageOriginal.GetHeight() / 2);
	
// Make a copy of the specific part
CImage imageNew;
imageNew.Create(rectCopy.Width(), rectCopy.Height(), imageOriginal.GetBPP());
imageOriginal.BitBlt(imageNew.GetDC(), rectCopy, rectCopy.TopLeft());
imageNew.ReleaseDC();

// Now imageNew holds the copy of the specific part from original image

I hope this helps! Smile | :)

Nuri Ismail

Game-point16-Sep-09 20:46

Re: Create new bitmap from oldbitmap [modified]

16-Sep-09 20:46

CImage imageOriginal;
imageOriginal.Load(_T( "read.tif" ));

// Here is the rect that we will copy from the original image (in this case 1/4 of it)
//CRect rectCopy(0, 0, imageOriginal.GetWidth() / 2, imageOriginal.GetHeight() / 2);

<code>CRect rectCopy(9177,68, 10566, 635);</code>

// Make a copy of the specific part
CImage imageNew;
imageNew.Create(rectCopy.Width(), rectCopy.Height(), imageOriginal.GetBPP());
imageOriginal.BitBlt(imageNew.GetDC(), rectCopy, rectCopy.TopLeft());
imageNew.Save(_T("D://imgnew.jpg"));

imageNew.ReleaseDC();

when i gave this rect portion ..the saving images contains ..full black

~~~~~~~~~~~~~Raju~~~~~~~~~~~~~

Nuri Ismail16-Sep-09 22:04

Nuri Ismail

16-Sep-09 22:04

rajugis wrote:
when i gave this rect portion ..the saving images contains ..full black

I think this problem could occur when your original image is indexed. You can read about indexed colors here[^].

If we want to copy indexed images we have to copy their color tables too. We can easily do this with CImage class. Smile | :)

First we have to check if the image is indexed and if it is than copy its color table, just like that:

// Check for color table after the creation of the new image
if(imageOriginal.IsIndexed())
{
	// If there is a color table for the original image
	// copy this table for the new image too.
	const int nMaxColors = imageOriginal.GetMaxColorTableEntries();
	RGBQUAD* pColorTable = new RGBQUAD[nMaxColors];
	imageOriginal.GetColorTable(0, nMaxColors, pColorTable);
	imageNew.SetColorTable(0, nMaxColors, pColorTable);
	delete [] pColorTable;
}

This code must be inserted after the creation of the new image. I've made a test application and it works fine for me for both indexed and on-indexed TIFFs. Here is the complete method:

void CTestCImageAppDlg::OnBnClickedButtonTest()
{
	// First load the original image
	CImage imageOriginal;
	HRESULT hrLoad = imageOriginal.Load(_T("D:\\testImg1.tif"));
	if(FAILED(hrLoad))
	{
		CString msg;
		msg.Format(_T("Error on load. Code:%08x"), hrLoad);
		AfxMessageBox(msg);
		return;
	}
	
	// Here is the rect that we will copy from the original image (in this case 1/4 of it)
	CRect rectCopy(0, 0, imageOriginal.GetWidth() / 2, imageOriginal.GetHeight() / 2);

	// Create the new image
	CImage imageNew;
	imageNew.Create(rectCopy.Width(), rectCopy.Height(), imageOriginal.GetBPP());
	
	// Check the original image for color table 
        // after the creation of the new image
	if(imageOriginal.IsIndexed())
	{
		// If there is a color table for the original image
		// copy this table for the new image too.
		const int nMaxColors = imageOriginal.GetMaxColorTableEntries();
		RGBQUAD* pColorTable = new RGBQUAD[nMaxColors];
		imageOriginal.GetColorTable(0, nMaxColors, pColorTable);
		imageNew.SetColorTable(0, nMaxColors, pColorTable);
		delete [] pColorTable;
	}

        CRect rect(rectCopy);
        rect.OffsetRect(-rectCopy.left, -rectCopy.top);
	
        // Now we can blit the original image on the new image
	imageOriginal.BitBlt(imageNew.GetDC(), rect, rectCopy.TopLeft());

	// It is good to release the DC first
	imageNew.ReleaseDC();


	// Lets save the new image
	HRESULT hrSave = imageNew.Save(_T("D:\\testImg2.tif"), Gdiplus::ImageFormatTIFF);
	if(FAILED(hrSave))
	{
		CString msg;
		msg.Format(_T("Error on save. Code:%08x"),hrSave);
		AfxMessageBox(msg);
		return;
	}
}

I hope this helps you. Smile | :)

Regards
Nuri Ismail

modified on Thursday, September 17, 2009 4:12 AM

Game-point16-Sep-09 22:36

16-Sep-09 22:36

wow ..its great ...

thanks for your help ...............

really thanks Nuri !!!!!!11

~~~~~~~~~~~~~Raju~~~~~~~~~~~~~