Screenshot direct to System::Drawing::Bitmap^ variable? (Visual Studio, Managed C++)

OpenGL OpenGL: Basic Coding
1

Hey guys,

I have been searching for how to make screenshot function… Is there a way to store the image directly on a variable like this: System:: Drawing::Bitmap^ bmp = gcnew System:: Drawing::Bitmap(width, height);

Thank you very much!

2

With C++, il read the screen data like this :

unsigned char* image = (unsigned char*)malloc(sizeof(unsigned char) * 3 * with * height);
glReadPixels(0, 0, this->w_Width, this->w_Height, GL_RGB, GL_UNSIGNED_BYTE, image);

all the datas a re in image, then, the simplest (but no efficient ways) is to write this in a PPM files (big files but easy format to write):

void PPMWriter(unsigned char *in,char *name,int dimx, int dimy)
{

int i, j;
FILE fp = fopen(name, “wb”); / b - binary mode /
(void) fprintf(fp, "P6
%d %d
255
", dimx, dimy);
for (j = 0; j < dimy; ++j)
{
for (i = 0; i < dimx; ++i)
{
static unsigned char color[3];
color[0] = in[3i+3jdimy]; /* red /
color[1] = in[3i+3jdimy+1]; /* green /
color[2] = in[3i+3jdimy+2]; /* blue */
(void) fwrite(color, 1, 3, fp);
}
}
(void) fclose(fp);
}

I’dont know if MS C++ have specific function to vrite bmp or another format…

3

Thank you, bob.

I got it with the help of the SDL library…

With this code below, I get the screenshot saved on a bmp file

	int screen_width = 1024;
		int screen_height = 620;


		SDL_Surface * temp = SDL_CreateRGBSurface(SDL_SWSURFACE, screen_width, screen_height, 24, 0x000000FF, 0x0000FF00, 0x00FF0000, 0);

		char * pixels = new char[3 * screen_width * screen_height];

		glReadPixels(0, 0, screen_width, screen_height, GL_RGB, GL_UNSIGNED_BYTE, pixels);

		for (int i = 0; i < screen_height; i++)
			std::memcpy(((char *)temp->pixels) + temp->pitch * i, pixels + 3 * screen_width * (screen_height - i - 1), screen_width * 3);

		delete[] pixels;

		SDL_SaveBMP(temp, "pic.bmp");

		SDL_FreeSurface(temp);

And with this code below, I get the bmp file on my pictureBox when I click a button as I wanted…

private: System::Void button2_Click(System::Object^  sender, System::EventArgs^  e) {

		

			
			pictureBox2->Image = Image::FromFile("pic.bmp");
			pictureBox2->SizeMode = PictureBoxSizeMode::StretchImage;
			this->pictureBox2->Visible = true;


			



			 
}