forked from Lephenixnoir/gint
92 lines
2.2 KiB
C
92 lines
2.2 KiB
C
#include <gint/defs/types.h>
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#include <gint/display.h>
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#include "../render/render.h"
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/* TODO: These parameters will eventually be specified by the font */
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#define CHAR_SPACING 1
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#define PROP_SPACING 5
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/* dfont(): Set the default font for text rendering */
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font_t const *dfont(font_t const * font)
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{
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font_t const *old_font = topti_font;
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topti_font = font ? font : gint_default_font;
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return old_font;
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}
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/* topti_glyph_index(): Obtain the glyph index of a Unicode code point */
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int topti_glyph_index(font_t const *f, uint32_t code_point)
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{
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int glyph_start = 0;
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for(int i = 0; i < f->block_count; i++)
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{
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int diff = code_point - f->blocks[i].start;
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if(diff >= 0 && diff < f->blocks[i].length)
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{
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return glyph_start + diff;
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}
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glyph_start += f->blocks[i].length;
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}
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return -1;
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}
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/* topti_offset(): Use a font index to find the location of a glyph */
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int topti_offset(font_t const *f, uint glyph)
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{
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/* Non-proportional fonts don't need an index */
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if(!f->prop) return glyph * f->storage_size;
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uint8_t const *width = f->glyph_width;
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/* The index gives us the position of all glyphs whose IDs are
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multiples of 8. Start with a close one and iterate from there. */
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uint g = glyph & ~0x7;
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int offset = f->glyph_index[g >> 3];
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/* Traverse the width array (which is in bits) while converting to
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longword size */
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while(g < glyph) offset += (width[g++] * f->data_height + 31) >> 5;
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return offset;
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}
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/* dsize(): Get the width and height of rendered text */
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void dsize(const char *str, font_t const * f, int *w, int *h)
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{
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if(!f) f = topti_font;
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if(h) *h = f->line_height;
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if(!w) return;
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/* Width for monospaced fonts is easy, unfortunately we still need to
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compute the length of [str]. Critical applications might do the
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product themselves to avoid this cost. */
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if(!f->prop)
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{
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int length = 0;
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while(*str++) length++;
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*w = (f->width + CHAR_SPACING) * length - CHAR_SPACING;
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return;
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}
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/* For proportional fonts, fetch the width of each individual glyphs */
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int width = 0, c;
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while((c = *str++))
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{
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if(c == ' ')
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{
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width += PROP_SPACING + CHAR_SPACING;
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continue;
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}
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int glyph = topti_glyph_index(f, c);
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if(glyph >= 0) width += f->glyph_width[glyph] + CHAR_SPACING;
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}
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*w = width - CHAR_SPACING;
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}
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