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macOS: Fix color component mixup in gl_draw text rendering #947

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This commit is contained in:
Matthias Melcher 2024-04-05 18:02:39 +02:00
parent 807d205a3c
commit 20138be66b
1 changed files with 33 additions and 7 deletions
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40
src/gl_draw.cxx
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@ -365,6 +365,7 @@ private:
int width; // its width
float ratio; // used without rectangle texture
int scale; // 1 or 2 for low/high resolution
Fl_Color color;
} data;
data *fifo; // array of pile elements
int size_; // pile height
@ -415,7 +416,7 @@ void gl_texture_fifo::display_texture(int rank)
glPushAttrib(GL_ENABLE_BIT | GL_TEXTURE_BIT | GL_COLOR_BUFFER_BIT);
glDisable (GL_DEPTH_TEST); // ensure text is not removed by depth buffer test.
glEnable (GL_BLEND); // for text fading
glBlendFunc (GL_ONE, GL_ONE_MINUS_SRC_ALPHA); // ditto
glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); // ditto
glDisable(GL_LIGHTING);
GLfloat pos[4];
glGetFloatv(GL_CURRENT_RASTER_POSITION, pos);
@ -426,6 +427,10 @@ void gl_texture_fifo::display_texture(int rank)
glScalef (R/winw, R/winh, 1.0f);
glTranslatef (-winw/R, -winh/R, 0.0f);
if (has_texture_rectangle) {
// The texture map is already colored, but we still need to apply alpha.
GLfloat colors[4];
glGetFloatv(GL_CURRENT_COLOR, colors);
glColor4f(1.0f, 1.0f, 1.0f, colors[3]);
glEnable (GL_TEXTURE_RECTANGLE_ARB);
glBindTexture (GL_TEXTURE_RECTANGLE_ARB, fifo[rank].texName);
GLint height;
@ -444,6 +449,8 @@ void gl_texture_fifo::display_texture(int rank)
glTexCoord2f (fifo[rank].width, 0.0f); // draw lower right in world coordinates
glVertex2f (bounds.origin.x + bounds.size.width, bounds.origin.y);
// Restore the current color value.
glColor4fv(colors);
glEnd ();
} else {
glTranslatef(pos[0]*2/R, pos[1]*2/R, 0.0);
@ -492,12 +499,19 @@ int gl_texture_fifo::compute_texture(const char* str, int n)
void *base = NULL;
if (fl_mac_os_version < 100600) base = calloc(4*fifo[current].width, h);
CGContextRef save_gc = fl_gc;
fl_gc = CGBitmapContextCreate(base, fifo[current].width, h, 8, fifo[current].width*4, lut,
(CGBitmapInfo)(kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host));
// Create our bitmap in RGBA order (no matter what the host byte order is)
fl_gc = CGBitmapContextCreate(base, fifo[current].width, h, 8, fifo[current].width*4, lut, kCGImageAlphaPremultipliedLast);
CGColorSpaceRelease(lut);
// Note that glyphs in macOS can be colorful (Emojis, for example). So
// instead of caching a mask, we store the text in RGB plus A for
// antialiasing. Draw the text in the requested color, but don't apply user
// alpha yet. It is applied later at render time so it's mixed correctly
// with the background.
GLfloat colors[4];
glGetFloatv(GL_CURRENT_COLOR, colors);
fl_color((uchar)(colors[0]*255), (uchar)(colors[1]*255), (uchar)(colors[2]*255));
Fl_Color color = ((uchar)(colors[0]*255)<<24) | ((uchar)(colors[1]*255)<<16) | ((uchar)(colors[2]*255)<<8);
fifo[current].color = color;
fl_color(color);
CGContextTranslateCTM(fl_gc, 0, h - gl_scale*fl_descent());
CGContextScaleCTM(fl_gc, gl_scale, gl_scale);
fl_draw(str, n, 0, 0);
@ -506,7 +520,8 @@ int gl_texture_fifo::compute_texture(const char* str, int n)
glBindTexture (GL_TEXTURE_RECTANGLE_ARB, fifo[current].texName);
glTexParameteri(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glPixelStorei(GL_UNPACK_ROW_LENGTH, fifo[current].width);
glTexImage2D(GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA8, fifo[current].width, h, 0, GL_BGRA_EXT, GL_UNSIGNED_INT_8_8_8_8_REV, CGBitmapContextGetData(fl_gc));
// Convert the created text bitmap into an RGBA OpenGL texture map.
glTexImage2D(GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA8, fifo[current].width, h, 0, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8_REV, CGBitmapContextGetData(fl_gc));
glPopAttrib();
CGContextRelease(fl_gc);
fl_gc = save_gc;
@ -521,9 +536,20 @@ int gl_texture_fifo::compute_texture(const char* str, int n)
int gl_texture_fifo::already_known(const char *str, int n)
{
int rank;
GLfloat colors[4];
glGetFloatv(GL_CURRENT_COLOR, colors);
Fl_Color color = ((uchar)(colors[0]*255)<<24) | ((uchar)(colors[1]*255)<<16) | ((uchar)(colors[2]*255)<<8);
for ( rank = 0; rank <= last; rank++) {
if ( memcmp(str, fifo[rank].utf8, n) == 0 && fifo[rank].utf8[n] == 0 &&
fifo[rank].fdesc == gl_fontsize && fifo[rank].scale == gl_scale) return rank;
const data &ff = fifo[rank];
if ( (ff.fdesc == gl_fontsize)
&& (ff.scale == gl_scale)
&& (ff.color == color)
&& (ff.utf8 != NULL)
&& (memcmp(str, ff.utf8, n) == 0)
&& (ff.utf8[n] == 0))
{
return rank;
}
}
return -1;
}