Use halfblocks to double vertical resolution of media (#98)

halfblocks vertical, w00t #88

src/lib/libav.c

@@ -29,7 +29,7 @@ void ncvisual_destroy(ncvisual* ncv){
   }
 }
 
-static void
+/* static void
 print_frame_summary(const AVCodecContext* cctx, const AVFrame* f){
   char pfmt[128];
   av_get_pix_fmt_string(pfmt, sizeof(pfmt), f->format);
@@ -65,7 +65,7 @@ print_frame_summary(const AVCodecContext* cctx, const AVFrame* f){
           f->best_effort_timestamp,
           f->key_frame ? "" : "non-",
           f->quality);
-}
+}*/
 
 AVFrame* ncvisual_decode(struct ncvisual* nc, int* averr){
   bool have_frame = false;
@@ -151,6 +151,10 @@ ncvisual* ncplane_visual_open(struct ncplane* nc, const char* filename, int* ave
   memset(ncv, 0, sizeof(*ncv));
   ncv->ncp = nc;
   ncplane_dim_yx(nc, &ncv->dstheight, &ncv->dstwidth);
+  // FIXME we only want to do this if we're not already large enough to
+  // faithfully reproduce the image, methinks?
+  //ncv->dstwidth *= 2;
+  ncv->dstheight *= 2;
   *averr = avformat_open_input(&ncv->fmtctx, filename, NULL, NULL);
   if(*averr < 0){
     fprintf(stderr, "Couldn't open %s (%s)\n", filename, av_err2str(*averr));

src/lib/notcurses.c

@@ -1553,23 +1553,38 @@ int ncvisual_render(const ncvisual* ncv){
   ncplane_cursor_move_yx(ncv->ncp, 0, 0);
   const int linesize = f->linesize[0];
   const unsigned char* data = f->data[0];
-  for(y = 0 ; y < f->height && y < dimy ; ++y){
+  for(y = 0 ; y < f->height / 2 && y < dimy ; ++y){
     for(x = 0 ; x < f->width && x < dimx ; ++x){
       int bpp = av_get_bits_per_pixel(av_pix_fmt_desc_get(f->format));
-      const unsigned char* rgbbase = data + (linesize * y) + (x * bpp / CHAR_BIT);
+      const unsigned char* rgbbase_up = data + (linesize * (y * 2)) + (x * bpp / CHAR_BIT);
+      const unsigned char* rgbbase_down = data + (linesize * (y * 2 + 1)) + (x * bpp / CHAR_BIT);
 /*fprintf(stderr, "[%04d/%04d] %p bpp: %d lsize: %d %02x %02x %02x %02x\n",
         y, x, rgbbase, bpp, linesize, rgbbase[0], rgbbase[1], rgbbase[2], rgbbase[3]);*/
       cell c = CELL_TRIVIAL_INITIALIZER;
-      if(!rgbbase[3]){
-        cell_fg_default(&c);
+      // use the default for the background, as that's the only way it's
+      // effective in that case anyway
+      if(!rgbbase_up[3] || !rgbbase_down[3]){
         cell_bg_default(&c);
-        if(cell_load(ncv->ncp, &c, " ") <= 0){
-          return -1;
+        if(!rgbbase_up[3] && !rgbbase_down[3]){
+          if(cell_load(ncv->ncp, &c, " ") <= 0){
+            return -1;
+          }
+          cell_fg_default(&c);
+        }else if(!rgbbase_up[3]){ // down has the color
+          if(cell_load(ncv->ncp, &c, "\u2584") <= 0){ // lower half block
+            return -1;
+          }
+          cell_set_fg(&c, rgbbase_down[0], rgbbase_down[1], rgbbase_down[2]);
+        }else{ // up has the color
+          if(cell_load(ncv->ncp, &c, "\u2580") <= 0){ // upper half block
+            return -1;
+          }
+          cell_set_fg(&c, rgbbase_up[0], rgbbase_up[1], rgbbase_up[2]);
         }
       }else{
-        cell_set_fg(&c, rgbbase[0], rgbbase[1], rgbbase[2]);
-        cell_set_bg(&c, rgbbase[0], rgbbase[1], rgbbase[2]);
-        if(cell_load(ncv->ncp, &c, "▓") <= 0){
+        cell_set_fg(&c, rgbbase_up[0], rgbbase_up[1], rgbbase_up[2]);
+        cell_set_bg(&c, rgbbase_down[0], rgbbase_down[1], rgbbase_down[2]);
+        if(cell_load(ncv->ncp, &c, "\u2580") <= 0){ // upper half block
           return -1;
         }
       }