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ASFont: access font pixels efficiently.

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Previous commit ensures that the font surface is always 32 bpp.
Therefore we can read font pixels directly through a pointer.
This commit is contained in:
Maarten ter Huurne 2011-05-12 02:10:40 +02:00
parent 41e6e4693e
commit a382a425a9
2 changed files with 39 additions and 61 deletions
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99
src/asfont.cpp
View File

@ -8,39 +8,6 @@
#define SFONTPLUS_CHARSET "!\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~¡¿ÀÁÈÉÌÍÒÓÙÚÝÄËÏÖÜŸÂÊÎÔÛÅÃÕÑÆÇČĎĚĽĹŇÔŘŔŠŤŮŽàáèéìíòóùúýäëïöüÿâêîôûåãõñæçčďěľĺňôřŕšťžůðßÐÞþАБВГДЕЁЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдеёжзийклмнопрстуфхцчшщъыьэюяØøąćęłńśżźĄĆĘŁŃŚŻŹ"
Uint32 ASFont::getPixel(Sint32 x, Sint32 y) {
assert(x>=0);
assert(x<surface->w);
assert(y>=0);
assert(y<surface->h);
Uint32 Bpp = surface->format->BytesPerPixel;
// Get the pixel
switch(Bpp) {
case 1:
return *((Uint8 *)surface->pixels + y * surface->pitch + x);
break;
case 2:
return *((Uint16 *)surface->pixels + y * surface->pitch/2 + x);
break;
case 3: { // Format/endian independent
Uint8 *bits = ((Uint8 *)surface->pixels)+y*surface->pitch+x*Bpp;
Uint8 r, g, b;
r = *((bits)+surface->format->Rshift/8);
g = *((bits)+surface->format->Gshift/8);
b = *((bits)+surface->format->Bshift/8);
return SDL_MapRGB(surface->format, r, g, b);
}
break;
case 4:
return *((Uint32 *)surface->pixels + y * surface->pitch/4 + x);
break;
}
return 0;
}
ASFont::ASFont(const std::string &fontImagePath)
: characters(SFONTPLUS_CHARSET)
{
@ -73,41 +40,53 @@ ASFont::ASFont(const std::string &fontImagePath)
surface = SDL_ConvertSurface(buf, &format32, SDL_SRCALPHA);
SDL_FreeSurface(buf);
}
assert(surface->format->BytesPerPixel == 4);
Uint32 pink = SDL_MapRGB(surface->format, 255,0,255);
unsigned c = 0;
SDL_LockSurface(surface);
for (unsigned x=0; x<(unsigned)surface->w && c<characters.length(); x++) {
if (getPixel(x,0) == pink) {
unsigned startx = x;
// Determine character widths.
Uint32 pink = SDL_MapRGB(surface->format, 255, 0, 255);
Uint32 *topLine = static_cast<Uint32 *>(surface->pixels);
const unsigned width = surface->w;
unsigned x = 0;
unsigned c = 0;
while (c < characters.length()) {
while (x < width && topLine[x] != pink) x++;
unsigned startx = x;
x++;
while (x < width && topLine[x] == pink) x++;
charpos.push_back(startx);
charpos.push_back(x);
if (c > 0 && utf8Code(characters[c - 1])) {
// UTF8 character
charpos.push_back(startx);
charpos.push_back(x);
x++;
while (x<(unsigned)surface->w && getPixel(x,0) == pink) x++;
charpos.push_back(x);
//utf8 characters
if (c>0 && utf8Code(characters[c-1])) {
charpos.push_back(startx);
charpos.push_back(x);
c++;
}
c++;
}
c++;
}
SDL_UnlockSurface(surface);
Uint32 colKey = getPixel(0,surface->h-1);
std::string::size_type pos = characters.find("0")*2;
SDL_Rect srcrect = {charpos[pos], 1, charpos[pos+2] - charpos[pos], surface->h - 1};
// Scan height of "0" glyph.
std::string::size_type pos = characters.find("0") * 2;
SDL_Rect srcrect = {
charpos[pos], 1, charpos[pos + 2] - charpos[pos], surface->h - 1
};
const unsigned alphaMask = surface->format->Amask;
unsigned y = srcrect.h;
bool nonKeyFound = false;
while (y-- > 0 && !nonKeyFound) {
unsigned x = srcrect.w;
while (x-- > 0 && !nonKeyFound)
nonKeyFound = getPixel(x+srcrect.x,y+srcrect.y) != colKey;
bool nonTransparentFound = false;
while (!nonTransparentFound && y-- > 0) {
Uint32 *line = reinterpret_cast<Uint32 *>(
reinterpret_cast<Uint8 *>(surface->pixels)
+ (srcrect.y + y) * surface->pitch
);
for (unsigned x = 0; !nonTransparentFound && x < srcrect.w; x++) {
nonTransparentFound = (line[srcrect.x + x] & alphaMask) != 0;
}
}
lineHeight = y+1;
lineHeight = y + 1;
SDL_UnlockSurface(surface);
}
ASFont::~ASFont() {

1
src/asfont.h
View File

@ -35,7 +35,6 @@ public:
void write(Surface* surface, const std::string& text, int x, int y, HAlign halign = HAlignLeft, VAlign valign = VAlignTop);
private:
Uint32 getPixel(Sint32 x, Sint32 y);
void write(SDL_Surface *surface, const std::string &text, int x, int y);
void write(SDL_Surface *surface, const std::string &text, int x, int y, HAlign halign);
void write(SDL_Surface *surface, const std::string &text, int x, int y, HAlign halign, VAlign valign);