new 'gradients' PoC #920

include/notcurses/notcurses.h

@@ -137,6 +137,9 @@ mbswidth(const char* mbs){
   (((((uint64_t)(fr) << 16u) + ((uint64_t)(fg) << 8u) + (uint64_t)(fb)) << 32ull) + \
    (((br) << 16u) + ((bg) << 8u) + (bb)) + CELL_BGDEFAULT_MASK + CELL_FGDEFAULT_MASK)
 
+#define CHANNEL_RGB_INITIALIZER(r, g, b) \
+  (((uint32_t)r << 16u) + ((uint32_t)g << 8u) + (b) + CELL_BGDEFAULT_MASK)
+
 // These lowest-level functions manipulate a 64-bit channel encoding directly.
 // Users will typically manipulate ncplane and cell channels through those APIs,
 // rather than calling these directly.

src/poc/gradients.c

@@ -0,0 +1,79 @@
+#include <unistd.h>
+#include <locale.h>
+#include <stdlib.h>
+#include <notcurses/notcurses.h>
+
+// gradient of 'A's changing color and background changing in reverse
+static int
+gradientA(struct notcurses* nc){
+  int dimy, dimx;
+  struct ncplane* stdn = notcurses_stddim_yx(nc, &dimy, &dimx);
+  uint64_t ul = CHANNELS_RGB_INITIALIZER(0, 0, 0, 0xff, 0xff, 0xff);
+  uint64_t ur = CHANNELS_RGB_INITIALIZER(0, 0xff, 0xff, 0xff, 0, 0);
+  uint64_t ll = CHANNELS_RGB_INITIALIZER(0xff, 0, 0, 0, 0xff, 0xff);
+  uint64_t lr = CHANNELS_RGB_INITIALIZER(0xff, 0xff, 0xff, 0, 0, 0);
+  if(ncplane_gradient(stdn, "A", NCSTYLE_NONE, ul, ur, ll, lr, dimy - 1, dimx - 1) <= 0){
+    return -1;
+  }
+  if(notcurses_render(nc)){
+    return -1;
+  }
+  sleep(3);
+  return 0;
+}
+
+static int
+gradStriations(struct notcurses* nc){
+  int dimy, dimx;
+  struct ncplane* stdn = notcurses_stddim_yx(nc, &dimy, &dimx);
+  uint64_t ul = CHANNELS_RGB_INITIALIZER(0, 0, 0, 0xff, 0xff, 0xff);
+  uint64_t ur = CHANNELS_RGB_INITIALIZER(0, 0xff, 0xff, 0xff, 0, 0);
+  uint64_t ll = CHANNELS_RGB_INITIALIZER(0xff, 0, 0, 0, 0xff, 0xff);
+  uint64_t lr = CHANNELS_RGB_INITIALIZER(0xff, 0xff, 0xff, 0, 0, 0);
+  if(ncplane_gradient(stdn, "▀", NCSTYLE_NONE, ul, ur, ll, lr, dimy - 1, dimx - 1) <= 0){
+    return -1;
+  }
+  if(notcurses_render(nc)){
+    return -1;
+  }
+  sleep(3);
+  return 0;
+}
+
+// gradient of 'A's changing color and background changing in reverse
+static int
+gradHigh(struct notcurses* nc){
+  int dimy, dimx;
+  struct ncplane* stdn = notcurses_stddim_yx(nc, &dimy, &dimx);
+  uint64_t ul = CHANNEL_RGB_INITIALIZER(0, 0, 0);
+  uint64_t ur = CHANNEL_RGB_INITIALIZER(0, 0xff, 0xff);
+  uint64_t ll = CHANNEL_RGB_INITIALIZER(0xff, 0, 0);
+  uint64_t lr = CHANNEL_RGB_INITIALIZER(0xff, 0xff, 0xff);
+  if(ncplane_highgradient(stdn, ul, ur, ll, lr, dimy - 1, dimx - 1) <= 0){
+    return -1;
+  }
+  if(notcurses_render(nc)){
+    return -1;
+  }
+  sleep(3);
+  return 0;
+}
+
+int main(void){
+  if(setlocale(LC_ALL, "") == NULL){
+    return EXIT_FAILURE;
+  }
+  struct notcurses_options opts = {
+    .flags = NCOPTION_INHIBIT_SETLOCALE,
+  };
+  struct notcurses* nc = notcurses_init(&opts, NULL);
+  if(nc == NULL){
+    return EXIT_FAILURE;
+  }
+  // no short-circuiting, intentional |
+  int ret = gradientA(nc) | gradStriations(nc) | gradHigh(nc);
+  if(notcurses_stop(nc) || ret){
+    return EXIT_FAILURE;
+  }
+  return EXIT_SUCCESS;
+}