ncvisual_from_plane() #559

CHANGELOG.md

@@ -1,7 +1,7 @@
 This document attempts to list user-visible changes and any major internal
 rearrangements of Notcurses.
 
-* 1.3.4 (not yet released)
+* 1.3.4 (2020-05-06)
   * `notcurses_lex_margins()` has been added to lex margins expressed in either
     of two canonical formats. Hopefully this will lead to more programs
     supporting margins.
@@ -13,7 +13,8 @@ rearrangements of Notcurses.
     radians on `ncvisual` objects.
   * `ncvisual_from_plane()` has been added to support "promotion" of an
     `ncplane` to an `ncvisual`. The source plane may contain only spaces,
-    half blocks, and full blocks.
+    half blocks, and full blocks. This builds atop the new function
+    `ncplane_rgba()`, which makes an RGBA flat array from an `ncplane`.
 
 * 1.3.3 (2020-04-26)
   * The `ncdplot` type has been added for plots based on `double`s rather than

USAGE.md

@@ -725,6 +725,13 @@ char* ncplane_at_yx(struct ncplane* n, int y, int x,
 // invalidated if the associated plane is destroyed.
 int ncplane_at_yx_cell(struct ncplane* n, int y, int x, cell* c);
 
+// Create an RGBA flat array from the selected region of the ncplane 'nc'.
+// Start at the plane's 'begy'x'begx' coordinate (which must lie on the
+// plane), continuing for 'leny'x'lenx' cells. Either or both of 'leny' and
+// 'lenx' can be specified as -1 to go through the boundary of the plane.
+uint32_t* ncplane_rgba(const struct ncplane* nc, int begy, int begx,
+                       int leny, int lenx);
+
 // Manipulate the opaque user pointer associated with this plane.
 // ncplane_set_userptr() returns the previous userptr after replacing
 // it with 'opaque'. the others simply return the userptr.
@@ -1196,6 +1203,8 @@ int ncblit_rgba(struct ncplane* nc, int placey, int placex, int linesize,
                 int leny, int lenx);
 ```
 
+
+
 ### Plane channels API
 
 Helpers are provided to manipulate an `ncplane`'s `channels` member. They are

doc/man/man3/notcurses_plane.3.md

@@ -50,6 +50,8 @@ notcurses_plane - operations on ncplanes
 
 **int ncplane_at_yx_cell(struct ncplane* n, int y, int x, cell* c);**
 
+**uint32_t* ncplane_rgba(const struct ncplane* nc, int begy, int begx, int leny, int lenx);**
+
 **void* ncplane_set_userptr(struct ncplane* n, void* opaque);**
 
 **void* ncplane_userptr(struct ncplane* n);**

include/notcurses/notcurses.h

@@ -1184,6 +1184,13 @@ ncplane_at_yx_cell(struct ncplane* n, int y, int x, cell* c){
   return r;
 }
 
+// Create an RGBA flat array from the selected region of the ncplane 'nc'.
+// Start at the plane's 'begy'x'begx' coordinate (which must lie on the
+// plane), continuing for 'leny'x'lenx' cells. Either or both of 'leny' and
+// 'lenx' can be specified as -1 to go through the boundary of the plane.
+API uint32_t* ncplane_rgba(const struct ncplane* nc, int begy, int begx,
+                           int leny, int lenx);
+
 // Manipulate the opaque user pointer associated with this plane.
 // ncplane_set_userptr() returns the previous userptr after replacing
 // it with 'opaque'. the others simply return the userptr.

python/src/notcurses/build_notcurses.py

@@ -141,6 +141,7 @@ char* ncplane_at_cursor(struct ncplane* n, uint32_t* attrword, uint64_t* channel
 int ncplane_at_cursor_cell(struct ncplane* n, cell* c);
 char* ncplane_at_yx(struct ncplane* n, int y, int x, uint32_t* attrword, uint64_t* channels);
 int ncplane_at_yx_cell(struct ncplane* n, int y, int x, cell* c);
+uint32_t* ncplane_rgba(const struct ncplane* nc, int begy, int begx, int leny, int lenx);
 void* ncplane_set_userptr(struct ncplane* n, void* opaque);
 void* ncplane_userptr(struct ncplane* n);
 int ncplane_resize(struct ncplane* n, int keepy, int keepx, int keepleny,

src/lib/notcurses.c

@@ -1965,3 +1965,29 @@ ncplane* rotate_plane(const ncplane* n){
   ncplane* newp = ncplane_new(n->nc, newy, newx, absy, absx, n->userptr);
   return newp;
 }
+
+uint32_t* ncplane_rgba(const ncplane* nc, int begy, int begx, int leny, int lenx){
+  if(begy < 0 || begx < 0){
+    return NULL;
+  }
+  if(begx >= nc->lenx || begy >= nc->leny){
+    return NULL;
+  }
+  if(lenx == -1){ // -1 means "to the end"; use all space available
+    lenx = nc->lenx - begx;
+  }
+  if(leny == -1){
+    leny = nc->leny - begy;
+  }
+  if(lenx < 0 || leny < 0){ // no need to draw zero-size object, exit
+    return NULL;
+  }
+  if(begx + lenx > nc->lenx || begy + leny > nc->leny){
+    return NULL;
+  }
+  uint32_t* ret = malloc(sizeof(*ret) * lenx * leny);
+  if(ret){
+    // FIXME populate via traversal
+  }
+  return ret;
+}

src/lib/visual.cpp

@@ -94,10 +94,20 @@ ncvisual* ncvisual_create(float timescale){
 }
 
 struct ncvisual* ncvisual_from_plane(ncplane* n){
+  uint32_t* rgba = ncplane_rgba(n, 0, 0, -1, -1);
+  if(rgba == NULL){
+    return NULL;
+  }
   int dimy, dimx;
   ncplane_dim_yx(n, &dimy, &dimx);
-  struct ncvisual* ncv = ncvisual_create(1);
-  // FIXME populate via ncplane_at_yx() traversal
+  struct ncvisual* ncv = ncvisual_from_rgba(n->nc, rgba, n->leny, n->lenx * 4, n->lenx);
+  if(ncv == NULL){
+    free(rgba);
+    return NULL;
+  }
+  ncplane_destroy(ncv->ncp);
+  ncv->ncp = n;
+  ncv->ncobj = NULL;
   return ncv;
 }
 
@@ -284,7 +294,7 @@ int ncvisual_render(const ncvisual* ncv, int begy, int begx, int leny, int lenx)
   if(leny == -1){
     leny = ncv->dstheight - begy;
   }
-  if(lenx == 0 || leny == 0){ // no need to draw zero-size object, exit
+  if(lenx < 0 || leny < 0){ // no need to draw zero-size object, exit
     return 0;
   }
   if(begx + lenx > ncv->dstwidth || begy + leny > ncv->dstheight){