Import Adobe Photoshop (.psd) images

• Download source files - 10 KB
• Download demo project - 168 KB
• Download images - 452 KB

Introduction

MyPSD::CPSD class is a C++ class that can load images saved in Adobe's Photoshop native format. Due to my new job I had to upgrade to Visual Studio 2005, but still the class is as portable as possible, hence it uses standard C++ and STL. With minor changes, it can be ported to Visual Studio 6 (uses an older version of STL) or even to other Operating Systems.

License

The class MyPSD::CPSD is free; but if you are to use it in any kind of software, especially commercial ones, I would appreciate if you could just email me, it's nice to learn that something you've written is used by others.

Using MyPSD::CPSD in your projects

To use the class, just include in your project the two files MyPSD.h/.cpp. Since the class is placed inside its own namespace, either use the full name MyPSD::CPSD psd; or first the directive using namespace MyPSD; and then just declare a local variable CPSD psd;.

How to use MyPSD::CPSD

MyPSD::CPSD psd; int nErrorCode = psd.Load("c:\\image.psd");
if ( 0 == nErrorCode )   // No errors were found
{
     int nDPI_x, nDPI_y; // for Horizontal & Vertical dpi
     int nWidth, nHeight; // for Width & Height in pixels
     psd.Dimensions(nWidth, nHeight);
     psd.DPI(nDPI_x, nDPI_y);
     HBITMAP hBitmap = psd.Detach();
}
else if ( -1 == nErrorCode ) // Cannot open file
     ; // Do something
else if ( -2 == nErrorCode ) // Error in the header of the file
     ; // Do something 
else if ( -3 == nErrorCode ) // Error in ColourMode Data, i.e. Palette
     ; // Do something       // File must be Index to have ColourMode Data 
else if ( -4 == nErrorCode ) // Error in ImageResource section of the file
     ; // Do something
else if ( -5 == nErrorCode ) // Error in Mask Info section of the file
     ; // Do something 
else if ( -6 == nErrorCode ) // Error in Image Data section of the file
     ; // Do something       // Actual data for pixels 
else if ( -7 == nErrorCode ) // Image is Black & White
     ; // Do something       // not yet implemented 
else if ( -8 == nErrorCode ) // An unsupported file format encountered
     ; // Do something 
else if ( -9 == nErrorCode ) // Cannot create HBITMAP handle
     ; // Do something 
else if ( -10 == nErrorCode ) // Data are compressed
     ; // Do something        // Zip format without prediction. Not yet
                              // implemented 
else if ( -11 == nErrorCode ) // Data are compressed
     ; // Do something        // Zip format with prediction. Not yet 
                              // implemented 
else if ( -12 == nErrorCode ) // Data are in an unknown format
     ; // Do something

How to make it compatible to Visual Studio 6

The STL that comes with Visual Studio 6 does not support the method push_back for std::string. One way is to use CStrings, but then you will have to use MFC, and the other way is to make some minor changes where strings are used. I.e.:

std::string strOSType;
for(unsigned int nChar = 0; nChar < 4; ++nChar)
    strOSType.push_back(image_resource.OSType[nChar]);

std::string strOSType = "";
for(unsigned int nChar = 0; nChar < 4; ++nChar)
    strOSType += image_resource.OSType[nChar];

More info than necessary... future release... maybe

In the MyPsd.h file, I have put more info than is actually used in the demo, as my intention is someday to implement layers as they are supported in Photoshop. The way MyPSD::CPSD class is implemented in the current version, the HBITMAP that someone gets is the merged outcome of all layers. In the future, I will try to have each layer separately detached from the original image, but don't hold your breath as I don't know if I have enough free time to do so.

Supported Formats

RGB, Lab, CMY, CMYK, Indexed, Grayscale, Duotone. These formats could be uncompressed or compressed with RLE.

Unsupported Formats/Not yet implemented

Bitmap (Black & White), and any format that is compressed with ZIP with prediction and without prediction, and that is basically because I don't know the ZIP compression algorithm (with and without prediction).

Thanks

I would like to thank my mathematician friend Kostas Papamarinos who helped me translate the data from planar to RGB order, and all of you who are going to use my MyPSD::CPSD class and either send me an email or not.

What's new in version 1.0.0.4

• Bug fixes - For correctly rendering Grayscale and Duotone PSD files. Samples included in the images.zip file that previous version could not read. As Visual Studio 2005 is more strict to the standard C++ and I hated all the warnings I was getting I have used the proposed functions which supposedly are more secure. I would like to apologise for any inconvenience caused by this change. If there is any problem just replace them with their equivalent older versions. Finally, for the above mentioned reasons, I am using a function to convert doubles to integers, as I would like to avoid type casting either done by me or the system .

What's new in version 1.0.0.3

• Bug fixes - For correctly rendering PSD files. Each Image Resource Block includes a Pascal string, and the way I translated into C/C++ was not the proper way, as a result some files could not be read.

What's new in version 1.0.0.2

• Bug fixes - I've found out that my previous version had some minor memory leaks.

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)