Add PDF writer.

test/image/TestPngWriter.cpp

@@ -0,0 +1,31 @@
+#include "Image.h"
+#include "PngWriter.h"
+
+int main()
+{
+    unsigned width = 200;
+    unsigned height = 200;
+    unsigned numChannels = 3;
+    auto image = Image::Create(width, height);
+    image->SetNumChannels(numChannels);
+
+    std::vector<unsigned char> data(image->GetBytesPerRow()*height, 0);
+    for(unsigned jdx=0;jdx<height;jdx++)
+    {
+        const auto heightOffset = jdx*image->GetBytesPerRow();
+        for(unsigned idx=0;idx<width*numChannels;idx+=numChannels)
+        {
+            const auto index = heightOffset + idx;
+            data[index] = (idx%2 == 0) ? 255*jdx/(height+1) : 0;
+            data[index+1] = 0;
+            data[index+2] = 0;
+        }
+    }
+    image->SetData(data);
+
+    PngWriter writer;
+    writer.SetPath("test.png");
+    writer.Write(image);
+
+    return 0;
+}