Need help to have Bitmap class on Xamarin Forms. Maybe DependencyService for Android and IOS.
I found that Xamarin forms does not have System.Drawing.Bitmap, then I installed Nuget "System.Drawing.Common" from Microsoft. Then program compiles without errors. But when running I receive this error:
**Could not resolve type with token 01000116 from typeref (expected class 'System.Drawing.Bitmap' in assembly 'System.Drawing.Common, Version=4.0.1.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51')
**
Tried a Google Search but no solution.
What I am trying to do, is receive a Photo in byte[] string and convert it to Bitmap to scale and print.
This is the code:
Function is called as: byte[] _buffer = PrintImage(PHOTO);
public byte[] PrintImage(byte[] PHOTO)
{
Bitmap bmp;
using (var ms = new MemoryStream(PHOTO))
{
bmp = new Bitmap(ms);
}
BitmapData data = GetBitmapData(bmp);
BitArray dots = data.Dots;
byte[] width = BitConverter.GetBytes(data.Width);
int offset = 0;
MemoryStream stream = new MemoryStream();
BinaryWriter bw = new BinaryWriter(stream);
// center command
bw.Write(27);
bw.Write('a');
bw.Write(1);
// print image
bw.Write((char)0x1B);
bw.Write('@');
bw.Write((char)0x1B);
bw.Write('3');
bw.Write((byte)24);
while (offset < data.Height)
{
bw.Write((char)0x1B);
bw.Write('*'); // bit-image mode
bw.Write((byte)33); // 24-dot double-density
bw.Write(width[0]); // width low byte
bw.Write(width[1]); // width high byte
for (int x = 0; x < data.Width; ++x)
{
for (int k = 0; k < 3; ++k)
{
byte slice = 0;
for (int b = 0; b < 8; ++b)
{
int y = (((offset / 8) + k) * 8) + b;
// Calculate the location of the pixel we want in the bit array.
// It'll be at (y * width) + x.
int i = (y * data.Width) + x;
// If the image is shorter than 24 dots, pad with zero.
bool v = false;
if (i < dots.Length)
{
v = dots[i];
}
slice |= (byte)((v ? 1 : 0) << (7 - b));
}
bw.Write(slice);
}
}
offset += 24;
bw.Write((char)0x0A);
}
// Restore the line spacing to the default of 30 dots.
bw.Write((char)0x1B);
bw.Write('3');
bw.Write((byte)30);
bw.Flush();
byte[] bytes = stream.ToArray();
return bytes; // logo + Encoding.Default.GetString(bytes);
}
public BitmapData GetBitmapData(Bitmap bmp)
{
//using (var bitmap = (Bitmap)Bitmap.FromFile(bmpFileName))
using (var bitmap = bmp)
{
var threshold = 127;
var index = 0;
double multiplier = 300; // scale
double scale = (double)(multiplier / (double)bitmap.Width);
int xheight = (int)(bitmap.Height * scale);
int xwidth = (int)(bitmap.Width * scale);
var dimensions = xwidth * xheight;
var dots = new BitArray(dimensions);
for (var y = 0; y < xheight; y++)
{
for (var x = 0; x < xwidth; x++)
{
var _x = (int)(x / scale);
var _y = (int)(y / scale);
var color = bitmap.GetPixel(_x, _y);
var luminance = (int)(color.R * 0.3 + color.G * 0.59 + color.B * 0.11);
dots[index] = (luminance < threshold);
index++;
}
}
return new BitmapData()
{
Dots = dots,
Height = (int)(bitmap.Height * scale),
Width = (int)(bitmap.Width * scale)
};
}
}
public class BitmapData
{
public BitArray Dots
{
get;
set;
}
public int Height
{
get;
set;
}
public int Width
{
get;
set;
}
}