[imageview] add small imageview demo program

Author: okay

src/imageview/Makefile

@@ -0,0 +1,6 @@
+EXE=imageview
+FILES=main.cpy
+
+include ../actions.make
+
+ASSET_DIR=assets/

src/imageview/main.cpy

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+#include "../build/rmkit.h"
+
+class App:
+  public:
+
+  def open_image(string full_path):
+    fb := framebuffer::get()
+    fb->clear_screen()
+    int iw, ih
+    int channels // an output parameter
+    decoded := (uint8_t*) stbi_load(full_path.c_str(), &iw, &ih, &channels, 4)
+
+    nw, nh := fb->get_display_size()
+    debug "RESIZING TO", nw, nh, channels
+    dst := (uint8_t*) malloc(nw * nh * 4)
+
+    aspect_ratio := std::min(nw / (float) iw, nh / (float) ih)
+
+    fw := aspect_ratio * iw
+    fh := aspect_ratio * ih
+
+    image := image_data{(uint32_t*) decoded, (int) iw, (int) ih, 4}
+    util::resize_image(image, fw, fh, 999)
+    fb->draw_bitmap(image,0,0)
+
+
+  def run():
+    ui::MainLoop::refresh()
+    ui::MainLoop::redraw()
+
+
+def main(int argc, char *argv[]):
+  App app
+  string img = "src/dithering_demo/colorspace.png"
+  fb := framebuffer::get()
+  fb->dither = framebuffer::DITHER::BAYER_2
+  if argc > 1:
+    img = argv[1]
+  else:
+    print "Usage:", argv[0], "<image file>"
+
+  app.open_image(img)
+  app.run()