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Add extend API for text measurement (bug 4515) and improve *_Wrapped …
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…functions

Bug 4515:
  - add an extend API for text measurement without rendering
  e.g: functions named TTF_Measure*()

*_Wrapped functions:
  - text is measured to foresee the wrapping, it avoids to have too many
    calls to Size() functions
  - 'words' that wouldn't fit within the wrap length are now cut.
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@1bsyl
1bsyl committed Mar 25, 2019
1 parent 42af6ad commit 0b24720
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Showing 2 changed files with 141 additions and 83 deletions.
209 changes: 127 additions & 82 deletions SDL_ttf.c
View file
Expand Up @@ -245,7 +245,11 @@ typedef enum {
static int TTF_initFontMetrics(TTF_Font *font);

static int TTF_Size_Internal(TTF_Font *font, const char *text, const str_type_t str_type,
int *w, int *h, int *xstart, int *ystart);
int *w, int *h, int *xstart, int *ystart, int measure_width, int *extent, int *count);

#define NO_MEASUREMENT \
0, NULL, NULL


static SDL_Surface* TTF_Render_Internal(TTF_Font *font, const char *text, const str_type_t str_type,
SDL_Color fg, SDL_Color bg, const render_mode_t render_mode);
Expand Down Expand Up @@ -2389,7 +2393,8 @@ int TTF_GlyphMetrics(TTF_Font *font, Uint16 ch,

static int TTF_Size_Internal(TTF_Font *font,
const char *text, const str_type_t str_type,
int *w, int *h, int *xstart, int *ystart)
int *w, int *h, int *xstart, int *ystart,
int measure_width, int *extent, int *count)
{
int x = 0;
int pos_x, pos_y;
Expand All @@ -2403,6 +2408,10 @@ static int TTF_Size_Internal(TTF_Font *font,
FT_Pos prev_delta = 0;
int prev_advance = 0;

/* Measurement mode */
int char_count = 0;
int current_width = 0;

TTF_CHECK_INITIALIZED(-1);
TTF_CHECK_POINTER(font, -1);
TTF_CHECK_POINTER(text, -1);
Expand Down Expand Up @@ -2506,6 +2515,16 @@ static int TTF_Size_Internal(TTF_Font *font,
maxx = SDL_max(maxx, pos_x + glyph->sz_width);
miny = SDL_min(miny, pos_y);
maxy = SDL_max(maxy, pos_y + glyph->sz_rows);

/* Measurement mode */
if (measure_width) {
int cw = maxx - minx;
if (cw >= measure_width) {
current_width = cw;
break;
}
char_count += 1;
}
}

/* Allows to render a string with only one space (bug 4344). */
Expand All @@ -2530,6 +2549,16 @@ static int TTF_Size_Internal(TTF_Font *font,
*h = (maxy - miny);
}

/* Measurement mode */
if (measure_width) {
if (extent) {
*extent = current_width;
}
if (count) {
*count = char_count;
}
}

if (utf8_alloc) SDL_stack_free(utf8_alloc);
return 0;
failure:
Expand All @@ -2539,17 +2568,32 @@ static int TTF_Size_Internal(TTF_Font *font,

int TTF_SizeText(TTF_Font *font, const char *text, int *w, int *h)
{
return TTF_Size_Internal(font, text, STR_TEXT, w, h, NULL, NULL);
return TTF_Size_Internal(font, text, STR_TEXT, w, h, NULL, NULL, NO_MEASUREMENT);
}

int TTF_SizeUTF8(TTF_Font *font, const char *text, int *w, int *h)
{
return TTF_Size_Internal(font, text, STR_UTF8, w, h, NULL, NULL);
return TTF_Size_Internal(font, text, STR_UTF8, w, h, NULL, NULL, NO_MEASUREMENT);
}

int TTF_SizeUNICODE(TTF_Font *font, const Uint16 *text, int *w, int *h)
{
return TTF_Size_Internal(font, (const char *)text, STR_UNICODE, w, h, NULL, NULL);
return TTF_Size_Internal(font, (const char *)text, STR_UNICODE, w, h, NULL, NULL, NO_MEASUREMENT);
}

int TTF_MeasureText(TTF_Font *font, const char *text, int width, int *extent, int *count)
{
return TTF_Size_Internal(font, text, STR_TEXT, NULL, NULL, NULL, NULL, width, extent, count);
}

int TTF_MeasureUTF8(TTF_Font *font, const char *text, int width, int *extent, int *count)
{
return TTF_Size_Internal(font, text, STR_UTF8, NULL, NULL, NULL, NULL, width, extent, count);
}

int TTF_MeasureUNICODE(TTF_Font *font, const Uint16 *text, int width, int *extent, int *count)
{
return TTF_Size_Internal(font, (const char *)text, STR_UNICODE, NULL, NULL, NULL, NULL, width, extent, count);
}

static SDL_Surface* TTF_Render_Internal(TTF_Font *font, const char *text, const str_type_t str_type,
Expand Down Expand Up @@ -2585,7 +2629,7 @@ static SDL_Surface* TTF_Render_Internal(TTF_Font *font, const char *text, const
}

/* Get the dimensions of the text surface */
if ((TTF_Size_Internal(font, text, STR_UTF8, &width, &height, &xstart, &ystart) < 0) || !width) {
if ((TTF_Size_Internal(font, text, STR_UTF8, &width, &height, &xstart, &ystart, NO_MEASUREMENT) < 0) || !width) {
TTF_SetError("Text has zero width");
goto failure;
}
Expand Down Expand Up @@ -2700,13 +2744,10 @@ SDL_Surface* TTF_RenderUNICODE_Blended(TTF_Font *font, const Uint16 *text, SDL_C
return TTF_Render_Internal(font, (const char *)text, STR_UNICODE, fg, fg /* unused */, RENDER_BLENDED);
}

static SDL_bool CharacterIsDelimiter(char c, const char *delimiters)
static SDL_bool CharacterIsDelimiter(char c)
{
while (*delimiters) {
if (c == *delimiters) {
return SDL_TRUE;
}
++delimiters;
if (c == ' ' || c == '\t' || c == '\r' || c == '\n') {
return SDL_TRUE;
}
return SDL_FALSE;
}
Expand All @@ -2720,7 +2761,7 @@ static SDL_Surface* TTF_Render_Wrapped_Internal(TTF_Font *font, const char *text
Uint8 *utf8_alloc = NULL;

int i, numLines, rowHeight, lineskip;
char *str = NULL, **strLines = NULL, **newLines = NULL;
char **strLines = NULL, *text_cpy;

TTF_CHECK_INITIALIZED(NULL);
TTF_CHECK_POINTER(font, NULL);
Expand All @@ -2734,7 +2775,7 @@ static SDL_Surface* TTF_Render_Wrapped_Internal(TTF_Font *font, const char *text
goto failure;
}
LATIN1_to_UTF8(text, utf8_alloc);
text = (const char *)utf8_alloc;
text_cpy = (char *)utf8_alloc;
} else if (str_type == STR_UNICODE) {
const Uint16 *text16 = (const Uint16 *) text;
utf8_alloc = SDL_stack_alloc(Uint8, UCS2_to_UTF8_len(text16));
Expand All @@ -2743,93 +2784,86 @@ static SDL_Surface* TTF_Render_Wrapped_Internal(TTF_Font *font, const char *text
goto failure;
}
UCS2_to_UTF8(text16, utf8_alloc);
text = (const char *)utf8_alloc;
text_cpy = (char *)utf8_alloc;
} else {
/* Use a copy anyway */
size_t str_len = SDL_strlen(text);
utf8_alloc = SDL_stack_alloc(Uint8, str_len + 1);
if (utf8_alloc == NULL) {
SDL_OutOfMemory();
goto failure;
}
SDL_memcpy(utf8_alloc, text, str_len + 1);
text_cpy = (char *)utf8_alloc;
}

/* Get the dimensions of the text surface */
if ((TTF_SizeUTF8(font, text, &width, &height) < 0) || !width) {
if ((TTF_SizeUTF8(font, text_cpy, &width, &height) < 0) || !width) {
TTF_SetError("Text has zero width");
goto failure;
}

numLines = 1;
str = NULL;
strLines = NULL;
if (wrapLength > 0 && *text) {
const char *wrapDelims = " \t\r\n";
int w, h;
char *spot, *tok, *next_tok, *end;
char delim;
size_t str_len = SDL_strlen(text);

if (wrapLength > 0 && *text_cpy) {
int maxNumLines = 0;
size_t textlen = SDL_strlen(text_cpy);
numLines = 0;

str = SDL_stack_alloc(char, str_len+1);
if (str == NULL) {
TTF_SetError("Out of memory");
goto failure;
}

SDL_strlcpy(str, text, str_len+1);
tok = str;
end = str + str_len;
do {
newLines = (char **)SDL_realloc(strLines, (numLines + 1) * sizeof (*strLines));
if (!newLines) {
TTF_SetError("Out of memory");
goto failure;
}
strLines = newLines;
strLines[numLines++] = tok;

/* Look for the end of the line */
if ((spot = SDL_strchr(tok, '\r')) != NULL ||
(spot = SDL_strchr(tok, '\n')) != NULL) {
if (*spot == '\r') {
++spot;
}
if (*spot == '\n') {
++spot;
int extent = 0, max_count = 0, char_count = 0;
size_t save_textlen = -1;
char *save_text = NULL;

if (numLines >= maxNumLines) {
char **saved = strLines;
maxNumLines += (width / wrapLength) + 1;
strLines = (char **)SDL_realloc(strLines, maxNumLines * sizeof (*strLines));
if (strLines == NULL) {
strLines = saved;
SDL_OutOfMemory();
goto failure;
}
} else {
spot = end;
}
next_tok = spot;

/* Get the longest string that will fit in the desired space */
for (; ;) {
/* Strip trailing whitespace */
while (spot > tok &&
CharacterIsDelimiter(spot[-1], wrapDelims)) {
--spot;

strLines[numLines++] = text_cpy;

if (TTF_MeasureUTF8(font, text_cpy, wrapLength, &extent, &max_count) < 0) {
TTF_SetError("Error measure text");
goto failure;
}

while (textlen > 0) {
Uint32 c = UTF8_getch(&text_cpy, &textlen);
if (c == UNICODE_BOM_NATIVE || c == UNICODE_BOM_SWAPPED) {
continue;
}
if (spot == tok) {
if (CharacterIsDelimiter(*spot, wrapDelims)) {
*spot = '\0';

char_count += 1;

/* Record last delimiter position */
if (CharacterIsDelimiter(c)) {
save_textlen = textlen;
save_text = text_cpy;
/* Break, if new line */
if (c == '\n' || c == '\r') {
*(text_cpy - 1) = '\0';
break;
}
break;
}
delim = *spot;
*spot = '\0';

TTF_SizeUTF8(font, tok, &w, &h);
if ((Uint32)w <= wrapLength) {
/* Break, if reach the limit */
if (char_count == max_count) {
break;
} else {
/* Back up and try again... */
*spot = delim;
}
}

while (spot > tok &&
!CharacterIsDelimiter(spot[-1], wrapDelims)) {
--spot;
}
if (spot > tok) {
next_tok = spot;
}
/* Cut at last delimiter/new lines, otherwise in the middle of the word */
if (save_text && textlen) {
text_cpy = save_text;
textlen = save_textlen;
}
tok = next_tok;
} while (tok < end);
} while (textlen > 0);
}

lineskip = TTF_FontLineSkip(font);
Expand Down Expand Up @@ -2860,13 +2894,19 @@ static SDL_Surface* TTF_Render_Wrapped_Internal(TTF_Font *font, const char *text
/* Render each line */
for (i = 0; i < numLines; i++) {
int xstart, ystart, line_width;
char save_c = 0;

/* Add end-of-line */
if (strLines) {
text = strLines[i];
if (i + 1 < numLines) {
save_c = strLines[i + 1][0];
strLines[i + 1][0] = '\0';
}
}

/* Initialize xstart, ystart and compute positions */
TTF_Size_Internal(font, text, STR_UTF8, &line_width, NULL, &xstart, &ystart);
TTF_Size_Internal(font, text, STR_UTF8, &line_width, NULL, &xstart, &ystart, NO_MEASUREMENT);

/* Move to i-th line */
ystart += i * lineskip;
Expand All @@ -2884,16 +2924,21 @@ static SDL_Surface* TTF_Render_Wrapped_Internal(TTF_Font *font, const char *text
if (TTF_HANDLE_STYLE_STRIKETHROUGH(font)) {
Draw_Line(textbuf, ystart + font->strikethrough_top_row, line_width, font->line_thickness, color, render_mode);
}

/* Remove end-of-line */
if (strLines) {
if (i + 1 < numLines) {
strLines[i + 1][0] = save_c;
}
}
}

if (strLines) SDL_free(strLines);
if (str) SDL_stack_free(str);
if (utf8_alloc) SDL_stack_free(utf8_alloc);
return textbuf;
failure:
if (textbuf) SDL_FreeSurface(textbuf);
if (strLines) SDL_free(strLines);
if (str) SDL_stack_free(str);
if (utf8_alloc) SDL_stack_free(utf8_alloc);
return NULL;
}
Expand Down
15 changes: 14 additions & 1 deletion SDL_ttf.h
View file
Expand Up @@ -169,13 +169,26 @@ extern DECLSPEC int SDLCALL TTF_GlyphIsProvided(TTF_Font *font, Uint16 ch);
*/
extern DECLSPEC int SDLCALL TTF_GlyphMetrics(TTF_Font *font, Uint16 ch,
int *minx, int *maxx,
int *miny, int *maxy, int *advance);
int *miny, int *maxy, int *advance);

/* Get the dimensions of a rendered string of text */
extern DECLSPEC int SDLCALL TTF_SizeText(TTF_Font *font, const char *text, int *w, int *h);
extern DECLSPEC int SDLCALL TTF_SizeUTF8(TTF_Font *font, const char *text, int *w, int *h);
extern DECLSPEC int SDLCALL TTF_SizeUNICODE(TTF_Font *font, const Uint16 *text, int *w, int *h);

/* Get the measurement string of text without rendering
e.g. the number of characters that can be rendered before reaching 'measure_width'
in:
measure_width - in pixels to measure this text
out:
count - number of characters that can be rendered
extent - latest calculated width
*/
extern DECLSPEC int SDLCALL TTF_MeasureText(TTF_Font *font, const char *text, int measure_width, int *extent, int *count);
extern DECLSPEC int SDLCALL TTF_MeasureUTF8(TTF_Font *font, const char *text, int measure_width, int *extent, int *count);
extern DECLSPEC int SDLCALL TTF_MeasureUNICODE(TTF_Font *font, const Uint16 *text, int measure_width, int *extent, int *count);

/* Create an 8-bit palettized surface and render the given text at
fast quality with the given font and color. The 0 pixel is the
colorkey, giving a transparent background, and the 1 pixel is set
Expand Down

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