update some definitions in USAGE.md

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nick black 2021-02-19 12:41:43 -05:00
parent 4951ea3d88
commit 925870bd7a
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2 changed files with 11 additions and 8 deletions

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@ -245,10 +245,10 @@ you off guard.
Utility functions operating on the toplevel `notcurses` object include:
```c
// Return the topmost ncplane, of which there is always at least one.
// Return the topmost ncplane of the standard pile.
struct ncplane* notcurses_top(struct notcurses* n);
// Return the bottommost ncplane, of which there is always at least one.
// Return the bottommost ncplane of the standard pile.
struct ncplane* notcurses_bottom(struct notcurses* n);
// Return our current idea of the terminal dimensions in rows and cols.
@ -2569,16 +2569,19 @@ channel_set(unsigned* channel, unsigned rgb){
// Extract the 2-bit alpha component from a 32-bit channel.
static inline unsigned
channel_alpha(unsigned channel){
return (channel & CELL_ALPHA_MASK) >> CELL_ALPHA_SHIFT;
return channel & CELL_BG_ALPHA_MASK;
}
// Set the 2-bit alpha component of the 32-bit channel.
static inline int
channel_set_alpha(unsigned* channel, unsigned alpha){
if(alpha < CELL_ALPHA_OPAQUE || alpha > CELL_ALPHA_TRANS){
if(alpha & ~CELL_BG_ALPHA_MASK){
return -1;
}
*channel = (alpha << CELL_ALPHA_SHIFT) | (*channel & ~CELL_ALPHA_MASK);
*channel = alpha | (*channel & ~CHANNEL_ALPHA_MASK);
if(alpha != CELL_ALPHA_OPAQUE){
*channel |= CELL_BGDEFAULT_MASK;
}
return 0;
}
@ -2894,7 +2897,7 @@ typedef enum {
NCSCALE_STRETCH,
} ncscale_e;
// Lex a visual scaling mode (one of "none", "stretch", or "scale").
// Lex a scaling mode (one of "none", "stretch", "scale", "nonehi", or "scalehi").
int notcurses_lex_scalemode(const char* op, ncscale_e* scalemode);
// Get the name of a scaling mode.

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@ -938,10 +938,10 @@ API int notcurses_render_to_buffer(struct notcurses* nc, char** buf, size_t* buf
// notcurses_render() has not yet been called, nothing will be written.
API int notcurses_render_to_file(struct notcurses* nc, FILE* fp);
// Return the topmost ncplane, of which there is always at least one.
// Return the topmost ncplane of the standard pile.
API struct ncplane* notcurses_top(struct notcurses* n);
// Return the bottommost ncplane, of which there is always at least one.
// Return the bottommost ncplane of the standard pile.
API struct ncplane* notcurses_bottom(struct notcurses* n);
// Destroy all ncplanes other than the stdplane.