add ncblit_rgb_packed(), ncblit_rgb_loose() #1634

NEWS.md

@@ -1,6 +1,10 @@
 This document attempts to list user-visible changes and any major internal
 rearrangements of Notcurses.
 
+* 2.2.11 (not yet released)
+  * Added `ncblit_rgb_loose()` and `ncblit_rgb_packed()` helpers for blitting
+    32bpp RGBx and 24bpp RGB.
+
 * 2.2.10 (2021-05-05)
   * Added `NCVISUAL_OPTION_CHILDPLANE` to interpret the `n` field of
     `ncvisual_options` as a parent plane.

USAGE.md

@@ -1565,6 +1565,16 @@ Raw streams of RGBA or BGRx data can be blitted directly to an ncplane:
 int ncblit_rgba(const void* data, int linesize,
                 const struct ncvisual_options* vopts);
 
+// Same as ncblit_rgba(), but for RGBx, with 'alpha' supplied as an alpha value
+// throughout, 0 <= 'alpha' <= 255. linesize ought be a multiple of 4.
+int ncblit_rgb_loose(const void* data, int linesize,
+                     const struct ncvisual_options* vopts, int alpha);
+
+// Same as ncblit_rgba(), but for RGB, with 'alpha' supplied as an alpha value
+// throughout, 0 <= 'alpha' <= 255. linesize ought be a multiple of 3.
+int ncblit_rgb_packed(const void* data, int linesize,
+                      const struct ncvisual_options* vopts, int alpha);
+
 // Same as ncblit_rgba(), but for BGRx.
 int ncblit_bgrx(const void* data, int linesize,
                 const struct ncvisual_options* vopts);

include/notcurses/notcurses.h

@@ -2610,6 +2610,16 @@ API int ncblit_rgba(const void* data, int linesize,
 API int ncblit_bgrx(const void* data, int linesize,
                     const struct ncvisual_options* vopts);
 
+// Supply an alpha value [0..255] to be applied throughout. linesize must be
+// a multiple of 3 for this RGB data.
+API int ncblit_rgb_packed(const void* data, int linesize,
+                          const struct ncvisual_options* vopts, int alpha);
+
+// Supply an alpha value [0..255] to be applied throughout. linesize must be
+// a multiple of 4 for this RGBx data.
+API int ncblit_rgb_loose(const void* data, int linesize,
+                         const struct ncvisual_options* vopts, int alpha);
+
 // The ncpixel API facilitates direct management of the pixels within an
 // ncvisual (ncvisuals keep a backing store of 32-bit RGBA pixels, and render
 // them down to terminal graphics in ncvisual_render()).

src/lib/blit.c

@@ -965,7 +965,35 @@ int ncblit_bgrx(const void* data, int linesize, const struct ncvisual_options* v
   if(vopts->leny <= 0 || vopts->lenx <= 0){
     return -1;
   }
-  void* rdata = bgra_to_rgba(data, vopts->leny, linesize, vopts->lenx);
+  void* rdata = bgra_to_rgba(data, vopts->leny, &linesize, vopts->lenx, 0xff);
+  if(rdata == NULL){
+    return -1;
+  }
+  int r = ncblit_rgba(rdata, linesize, vopts);
+  free(rdata);
+  return r;
+}
+
+int ncblit_rgb_loose(const void* data, int linesize,
+                     const struct ncvisual_options* vopts, int alpha){
+  if(vopts->leny <= 0 || vopts->lenx <= 0){
+    return -1;
+  }
+  void* rdata = rgb_loose_to_rgba(data, vopts->leny, &linesize, vopts->lenx, alpha);
+  if(rdata == NULL){
+    return -1;
+  }
+  int r = ncblit_rgba(rdata, linesize, vopts);
+  free(rdata);
+  return r;
+}
+
+int ncblit_rgb_packed(const void* data, int linesize,
+                      const struct ncvisual_options* vopts, int alpha){
+  if(vopts->leny <= 0 || vopts->lenx <= 0){
+    return -1;
+  }
+  void* rdata = rgb_packed_to_rgba(data, vopts->leny, &linesize, vopts->lenx, alpha);
   if(rdata == NULL){
     return -1;
   }

src/lib/internal.h

@@ -1146,7 +1146,9 @@ memdup(const void* src, size_t len){
   return ret;
 }
 
-ALLOC void* bgra_to_rgba(const void* data, int rows, int rowstride, int cols);
+ALLOC void* bgra_to_rgba(const void* data, int rows, int* rowstride, int cols, int alpha);
+ALLOC void* rgb_loose_to_rgba(const void* data, int rows, int* rowstride, int cols, int alpha);
+ALLOC void* rgb_packed_to_rgba(const void* data, int rows, int* rowstride, int cols, int alpha);
 
 // find the "center" cell of two lengths. in the case of even rows/columns, we
 // place the center on the top/left. in such a case there will be one more

src/lib/visual.c

@@ -212,23 +212,75 @@ int ncvisual_blitter_geom(const notcurses* nc, const ncvisual* n,
   return ret;
 }
 
-void* bgra_to_rgba(const void* data, int rows, int rowstride, int cols){
-  if(rowstride % 4){ // must be a multiple of 4 bytes
+void* rgb_loose_to_rgba(const void* data, int rows, int* rowstride, int cols, int alpha){
+  if(*rowstride % 4){ // must be a multiple of 4 bytes
     return NULL;
   }
-  uint32_t* ret = malloc(rowstride * rows);
+  if(*rowstride < cols * 4){
+    return NULL;
+  }
+  uint32_t* ret = malloc(4 * cols * rows);
+  if(ret){
+    for(int y = 0 ; y < rows ; ++y){
+      for(int x = 0 ; x < cols ; ++x){
+        const uint32_t* src = (const uint32_t*)data + (*rowstride / 4) * y + x;
+        uint32_t* dst = ret + cols * y + x;
+        ncpixel_set_a(dst, alpha);
+        ncpixel_set_r(dst, ncpixel_r(*src));
+        ncpixel_set_g(dst, ncpixel_g(*src));
+        ncpixel_set_b(dst, ncpixel_b(*src));
+      }
+    }
+  }
+  *rowstride = cols * 4;
+  return ret;
+}
+
+void* rgb_packed_to_rgba(const void* data, int rows, int* rowstride, int cols, int alpha){
+  if(*rowstride % 3){ // must be a multiple of 3 bytes
+    return NULL;
+  }
+  if(*rowstride < cols * 3){
+    return NULL;
+  }
+  uint32_t* ret = malloc(4 * cols * rows);
+  if(ret){
+    for(int y = 0 ; y < rows ; ++y){
+      for(int x = 0 ; x < cols ; ++x){
+        const unsigned char* src = (const unsigned char*)data + *rowstride * y + x;
+        uint32_t* dst = ret + cols * y + x;
+        ncpixel_set_a(dst, alpha);
+        ncpixel_set_r(dst, src[0]);
+        ncpixel_set_g(dst, src[1]);
+        ncpixel_set_b(dst, src[2]);
+      }
+    }
+  }
+  *rowstride = cols * 4;
+  return ret;
+}
+
+void* bgra_to_rgba(const void* data, int rows, int* rowstride, int cols, int alpha){
+  if(*rowstride % 4){ // must be a multiple of 4 bytes
+    return NULL;
+  }
+  if(*rowstride < cols * 4){
+    return NULL;
+  }
+  uint32_t* ret = malloc(4 * cols * rows);
   if(ret){
     for(int y = 0 ; y < rows ; ++y){
       for(int x = 0 ; x < cols ; ++x){
-        const uint32_t* src = (const uint32_t*)data + (rowstride / 4) * y + x;
-        uint32_t* dst = ret + (rowstride / 4) * y + x;
-        ncpixel_set_a(dst, 0xff);
+        const uint32_t* src = (const uint32_t*)data + (*rowstride / 4) * y + x;
+        uint32_t* dst = ret + cols * y + x;
+        ncpixel_set_a(dst, alpha);
         ncpixel_set_r(dst, ncpixel_b(*src));
         ncpixel_set_g(dst, ncpixel_g(*src));
         ncpixel_set_b(dst, ncpixel_r(*src));
       }
     }
   }
+  *rowstride = cols * 4;
   return ret;
 }