ncvisual_from_palidex

NEWS.md

@@ -20,6 +20,7 @@ rearrangements of Notcurses.
     the media of an `ncvisual`. As a result, it now returns a `ncplane*`
     rather than `char*`. I don't think anyone was using this, so hopefully
     that's ok.
+  * Add `ncvisual_from_palidx()`, which does what you would think.
 
 * 2.3.11 (2021-07-20)
   * Notcurses now requires libz to build. In exchange, it can now generate

USAGE.md

@@ -3134,6 +3134,13 @@ struct ncvisual* ncvisual_from_rgb_loose(const void* rgba, int rows,
 // ncvisual_from_rgba(), but for BGRA.
 struct ncvisual* ncvisual_from_bgra(struct notcurses* nc, const void* bgra,
                                     int rows, int rowstride, int cols);
+
+// ncvisual_from_rgba(), but 'data' is 'pstride'-byte palette-indexed pixels,
+// arranged in 'rows' lines of 'rowstride' bytes each, composed of 'cols'
+// pixels. 'palette' is an array of at least 'palsize' ncchannels.
+struct ncvisual* ncvisual_from_palidx(const void* data, int rows,
+                                      int rowstride, int cols, int palsize,
+                                      int pstride, const uint32_t* palette);
 ```
 
 `ncvisual`s can also be loaded from the contents of a plane:

doc/man/man3/notcurses_visual.3.md

@@ -62,6 +62,8 @@ typedef int (*streamcb)(struct notcurses*, struct ncvisual*, void*);
 
 **struct ncvisual* ncvisual_from_bgra(const void* ***bgra***, int ***rows***, int ***rowstride***, int ***cols***);**
 
+**struct ncvisual* ncvisual_from_palidx(const void* ***data***, int ***rows***, int ***rowstride***, int ***cols***, int ***palsize***, int ***pstride***, const uint32_t* ***palette***);**
+
 **struct ncvisual* ncvisual_from_plane(struct ncplane* ***n***, ncblitter_e ***blit***, int ***begy***, int ***begx***, int ***leny***, int ***lenx***);**
 
 **int ncvisual_blitter_geom(const struct notcurses* ***nc***, const struct ncvisual* ***n***, const struct ncvisual_options* ***vopts***, int* ***y***, int* ***x***, int* ***scaley***, int* ***scalex***, ncblitter_e* ***blitter***);**
@@ -138,6 +140,10 @@ resulting plane will be ceil(**rows**/2) rows, and **cols** columns.
 **ncvisual_from_rgb_loose** uses 4-byte RGBx source data. Both will fill in
 the alpha component of every target pixel with the specified **alpha**.
 
+**ncvisual_from_palidx** requires a ***palette*** of at least ***palsize***
+**ncchannel**s. Pixels are ***pstride*** bytes each, arranged as ***cols*** pixels
+per row, with each row occupying ***rowstride*** bytes, across ***rows*** rows.
+
 **ncvisual_from_plane** requires specification of a rectangle via ***begy***,
 ***begx***, ***leny***, and ***lenx***, and also a blitter. The only valid
 glyphs within this region are those used by the specified blitter.

include/notcurses/notcurses.h

@@ -2568,7 +2568,8 @@ ncplane_double_box_sized(struct ncplane* n, uint32_t styles, uint64_t channels,
 
 // Open a visual at 'file', extract a codec and parameters, decode the first
 // image to memory.
-API ALLOC struct ncvisual* ncvisual_from_file(const char* file);
+API ALLOC struct ncvisual* ncvisual_from_file(const char* file)
+  __attribute__ ((nonnull (1)));
 
 // Prepare an ncvisual, and its underlying plane, based off RGBA content in
 // memory at 'rgba'. 'rgba' is laid out as 'rows' lines, each of which is
@@ -2577,25 +2578,38 @@ API ALLOC struct ncvisual* ncvisual_from_file(const char* file);
 // of padding). The total size of 'rgba' is thus (rows * rowstride) bytes, of
 // which (rows * cols * 4) bytes are actual non-padding data.
 API ALLOC struct ncvisual* ncvisual_from_rgba(const void* rgba, int rows,
-                                              int rowstride, int cols);
+                                              int rowstride, int cols)
+  __attribute__ ((nonnull (1)));
 
 // ncvisual_from_rgba(), but the pixels are 3-byte RGB. A is filled in
 // throughout using 'alpha'.
 API ALLOC struct ncvisual* ncvisual_from_rgb_packed(const void* rgba, int rows,
                                                     int rowstride, int cols,
-                                                    int alpha);
+                                                    int alpha)
+  __attribute__ ((nonnull (1)));
 
 // ncvisual_from_rgba(), but the pixels are 4-byte RGBx. A is filled in
 // throughout using 'alpha'. rowstride must be a multiple of 4.
 API ALLOC struct ncvisual* ncvisual_from_rgb_loose(const void* rgba, int rows,
                                                    int rowstride, int cols,
-                                                   int alpha);
+                                                   int alpha)
+  __attribute__ ((nonnull (1)));
 
 // ncvisual_from_rgba(), but 'bgra' is arranged as BGRA. note that this is a
 // byte-oriented layout, despite being bunched in 32-bit pixels; the lowest
 // memory address ought be B, and A is reached by adding 3 to that address.
 API ALLOC struct ncvisual* ncvisual_from_bgra(const void* bgra, int rows,
-                                              int rowstride, int cols);
+                                              int rowstride, int cols)
+  __attribute__ ((nonnull (1)));
+
+// ncvisual_from_rgba(), but 'data' is 'pstride'-byte palette-indexed pixels,
+// arranged in 'rows' lines of 'rowstride' bytes each, composed of 'cols'
+// pixels. 'palette' is an array of at least 'palsize' ncchannels.
+API ALLOC struct ncvisual* ncvisual_from_palidx(const void* data, int rows,
+                                                int rowstride, int cols,
+                                                int palsize, int pstride,
+                                                const uint32_t* palette)
+  __attribute__ ((nonnull (1, 7)));
 
 // Promote an ncplane 'n' to an ncvisual. The plane may contain only spaces,
 // half blocks, and full blocks. The latter will be checked, and any other

src/lib/visual.c

@@ -693,6 +693,47 @@ ncvisual* ncvisual_from_bgra(const void* bgra, int rows, int rowstride, int cols
   return ncv;
 }
 
+ncvisual* ncvisual_from_palidx(const void* pdata, int rows, int rowstride,
+                               int cols, int palsize, int pstride,
+                               const uint32_t* palette){
+  if(rowstride % pstride){
+    logerror("bad pstride (%d) for rowstride (%d)\n", pstride, rowstride);
+    return NULL;
+  }
+  ncvisual* ncv = ncvisual_create();
+  if(ncv){
+    ncv->rowstride = pad_for_image(rowstride, cols);
+    ncv->pixx = cols;
+    ncv->pixy = rows;
+    uint32_t* data = malloc(ncv->rowstride * ncv->pixy);
+    if(data == NULL){
+      ncvisual_destroy(ncv);
+      return NULL;
+    }
+    for(int y = 0 ; y < rows ; ++y){
+      for(int x = 0 ; x < cols ; ++x){
+        int palidx = ((const unsigned char*)pdata)[y * rowstride + x * pstride];
+        if(palidx >= palsize){
+          free(data);
+          ncvisual_destroy(ncv);
+          logerror("invalid palette idx %d >= %d\n", palidx, palsize);
+          return NULL;
+        }
+        uint32_t src = palette[palidx];
+        uint32_t* dst = &data[ncv->rowstride * y / 4 + x];
+        ncpixel_set_a(dst, 255);
+        ncpixel_set_r(dst, 255);
+        ncpixel_set_g(dst, 255);
+        ncpixel_set_b(dst, 255); // FIXME pull out of palette
+//fprintf(stderr, "BGRA PIXEL: %02x%02x%02x%02x RGBA result: %02x%02x%02x%02x\n", ((const char*)&src)[0], ((const char*)&src)[1], ((const char*)&src)[2], ((const char*)&src)[3], ((const char*)dst)[0], ((const char*)dst)[1], ((const char*)dst)[2], ((const char*)dst)[3]);
+      }
+    }
+    ncvisual_set_data(ncv, data, true);
+    ncvisual_details_seed(ncv);
+  }
+  return ncv;
+}
+
 int ncvisual_resize(ncvisual* n, int rows, int cols){
   if(!visual_implementation.visual_resize){
     return ncvisual_resize_noninterpolative(n, rows, cols);