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Bring back simple grayscale rendering option

This commit is contained in:
Francesco Abbate 2020-06-11 23:11:40 +02:00
parent 00c3983da6
commit 93a36617f9
3 changed files with 70 additions and 110 deletions
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133
lib/font_renderer/font_renderer.cpp
View File

@ -15,9 +15,39 @@ struct FR_Bitmap {
int width, height;
};
typedef agg::blender_rgb_gamma<agg::rgba8, agg::order_bgra, agg::gamma_lut<> > blender_gamma_type;
class FR_Impl {
public:
// Conventional LUT values: (1./3., 2./9., 1./9.)
// The values below are fine tuned as in the Elementary Plot library.
FR_Bitmap* FR_Bitmap_New(int width, int height, int subpixel_scale) {
FR_Impl(bool hinting, bool kerning, bool subpixel, float gamma_value) :
m_renderer(hinting, kerning, subpixel),
m_gamma_lut(double(gamma_value)),
m_lcd_lut(0.448, 0.184, 0.092),
m_subpixel(subpixel)
{ }
font_renderer_alpha& renderer_alpha() { return m_renderer; }
agg::gamma_lut<>& gamma() { return m_gamma_lut; }
agg::lcd_distribution_lut& lcd_distribution_lut() { return m_lcd_lut; }
int subpixel_scale() const { return (m_subpixel ? 3 : 1); }
private:
font_renderer_alpha m_renderer;
agg::gamma_lut<> m_gamma_lut;
agg::lcd_distribution_lut m_lcd_lut;
int m_subpixel;
};
FontRenderer *FR_New(unsigned int flags, float gamma) {
bool hinting = ((flags & FR_HINTING) != 0);
bool kerning = ((flags & FR_KERNING) != 0);
bool subpixel = ((flags & FR_SUBPIXEL) != 0);
return new FR_Impl(hinting, kerning, subpixel, gamma);
}
FR_Bitmap* FR_Bitmap_New(FontRenderer *font_renderer, int width, int height) {
const int subpixel_scale = font_renderer->subpixel_scale();
FR_Bitmap *image = (FR_Bitmap *) malloc(sizeof(FR_Bitmap) + width * height * subpixel_scale);
if (!image) { return NULL; }
image->pixels = (agg::int8u *) (image + 1);
@ -30,39 +60,6 @@ void FR_Bitmap_Free(FR_Bitmap *image) {
free(image);
}
class FR_Impl {
public:
// Conventional LUT values: (1./3., 2./9., 1./9.)
// The values below are fine tuned as in the Elementary Plot library.
FR_Impl(bool hinting, bool kerning, bool subpixel, float gamma_value) :
m_renderer(hinting, kerning, subpixel),
m_gamma_lut(double(gamma_value)),
m_blender(),
m_lcd_lut(0.448, 0.184, 0.092)
{
m_blender.gamma(m_gamma_lut);
}
font_renderer_alpha& renderer_alpha() { return m_renderer; }
blender_gamma_type& blender() { return m_blender; }
agg::gamma_lut<>& gamma() { return m_gamma_lut; }
agg::lcd_distribution_lut& lcd_distribution_lut() { return m_lcd_lut; }
private:
font_renderer_alpha m_renderer;
agg::gamma_lut<> m_gamma_lut;
blender_gamma_type m_blender;
agg::lcd_distribution_lut m_lcd_lut;
};
FontRenderer *FR_New(unsigned int flags, float gamma) {
bool hinting = ((flags & FONT_RENDERER_HINTING) != 0);
bool kerning = ((flags & FONT_RENDERER_KERNING) != 0);
bool subpixel = ((flags & FONT_RENDERER_SUBPIXEL) != 0);
return new FR_Impl(hinting, kerning, subpixel, gamma);
}
void FR_Free(FontRenderer *font_renderer) {
delete font_renderer;
}
@ -171,9 +168,11 @@ static int ceil_to_multiple(int n, int p) {
int FR_Bake_Font_Bitmap(FontRenderer *font_renderer, int font_height,
FR_Bitmap *image,
int first_char, int num_chars, FR_Bitmap_Glyph_Metrics *glyphs, int subpixel_scale)
int first_char, int num_chars, FR_Bitmap_Glyph_Metrics *glyphs)
{
font_renderer_alpha& renderer_alpha = font_renderer->renderer_alpha();
agg::lcd_distribution_lut& lcd_lut = font_renderer->lcd_distribution_lut();
const int subpixel_scale = font_renderer->subpixel_scale();
agg::int8u *pixels = image->pixels;
const int pixels_width = image->width, pixels_height = image->height;
@ -190,7 +189,6 @@ int FR_Bake_Font_Bitmap(FontRenderer *font_renderer, int font_height,
const int pad_y = font_height / 10;
const int y_step = font_height + 2 * pad_y;
agg::lcd_distribution_lut& lcd_lut = font_renderer->lcd_distribution_lut();
agg::rendering_buffer ren_buf(pixels, pixels_width * subpixel_scale, pixels_height, -pixels_width * subpixel_scale * pixel_size);
// When using subpixel font rendering it is needed to leave a padding pixel on the left and on the right.
// Since each pixel is composed by n subpixel we set below x_start to subpixel_scale instead than zero.
@ -232,7 +230,7 @@ int FR_Bake_Font_Bitmap(FontRenderer *font_renderer, int font_height,
glyph_info.yoff = -pad_y;
glyph_info.xadvance = (x_next - x) / subpixel_scale;
if (glyph_info.x1 > glyph_info.x0) {
if (subpixel_scale != 1 && glyph_info.x1 > glyph_info.x0) {
glyph_lut_convolution(ren_buf, lcd_lut, cover_swap_buffer, glyph_info);
}
glyph_trim_rect(ren_buf, glyph_info, subpixel_scale);
@ -244,39 +242,29 @@ int FR_Bake_Font_Bitmap(FontRenderer *font_renderer, int font_height,
return res;
}
void blend_solid_hspan(agg::rendering_buffer& rbuf, blender_gamma_type& blender,
template <typename Order>
void blend_solid_hspan(agg::rendering_buffer& rbuf, agg::gamma_lut<>& gamma,
int x, int y, unsigned len,
const agg::rgba8& c, const agg::int8u* covers)
{
typedef typename blender_gamma_type::color_type color_type;
typedef typename blender_gamma_type::order_type order_type;
typedef typename color_type::value_type value_type;
typedef typename color_type::calc_type calc_type;
if (c.a)
{
value_type* p = (value_type*)rbuf.row_ptr(x, y, len) + (x << 2);
const int pixel_size = 4;
agg::int8u* p = rbuf.row_ptr(y) + x * pixel_size;
do
{
calc_type alpha = (calc_type(c.a) * (calc_type(*covers) + 1)) >> 8;
if(alpha == color_type::base_mask)
{
p[order_type::R] = c.r;
p[order_type::G] = c.g;
p[order_type::B] = c.b;
}
else
{
blender.blend_pix(p, c.r, c.g, c.b, alpha, *covers);
}
const unsigned alpha = *covers;
const unsigned r = gamma.dir(p[Order::R]), g = gamma.dir(p[Order::G]), b = gamma.dir(p[Order::B]);
p[Order::R] = gamma.inv((((gamma.dir(c.r) - r) * alpha) >> 8) + r);
p[Order::G] = gamma.inv((((gamma.dir(c.g) - g) * alpha) >> 8) + g);
p[Order::B] = gamma.inv((((gamma.dir(c.b) - b) * alpha) >> 8) + b);
// Leave p[3], the alpha channel value unmodified.
p += 4;
++covers;
}
while(--len);
}
}
void blend_solid_hspan_rgb_subpixel(agg::rendering_buffer& rbuf, agg::gamma_lut<>& gamma, agg::lcd_distribution_lut& lcd_lut,
template <typename Order>
void blend_solid_hspan_subpixel(agg::rendering_buffer& rbuf, agg::gamma_lut<>& gamma, agg::lcd_distribution_lut& lcd_lut,
const int x, const int y, unsigned len,
const agg::rgba8& c,
const agg::int8u* covers)
@ -286,7 +274,7 @@ void blend_solid_hspan_rgb_subpixel(agg::rendering_buffer& rbuf, agg::gamma_lut<
agg::int8u* p = rbuf.row_ptr(y) + x * pixel_size;
// Indexes to adress RGB colors in a BGRA32 format.
const int pixel_index[3] = {2, 1, 0};
const int pixel_index[3] = {Order::R, Order::G, Order::B};
for (unsigned cx = 0; cx < len; cx += 3)
{
for (int i = 0; i < 3; i++) {
@ -301,25 +289,12 @@ void blend_solid_hspan_rgb_subpixel(agg::rendering_buffer& rbuf, agg::gamma_lut<
}
}
#if 0
// destination implicitly BGRA32. Source implictly single-byte renderer_alpha coverage.
void FR_Blend_Gamma(FontRenderer *font_renderer, uint8_t *dst, int dst_stride, uint8_t *src, int src_stride, int region_width, int region_height, FR_Color color) {
blender_gamma_type& blender = font_renderer->blender();
agg::rendering_buffer dst_ren_buf(dst, region_width, region_height, dst_stride);
const agg::rgba8 color_a(color.r, color.g, color.b);
for (int x = 0, y = 0; y < region_height; y++) {
agg::int8u *covers = src + y * src_stride;
blend_solid_hspan(dst_ren_buf, blender, x, y, region_width, color_a, covers);
}
}
#endif
// destination implicitly BGRA32. Source implictly single-byte renderer_alpha coverage with subpixel scale = 3.
// FIXME: consider using something like RenColor* instead of uint8_t * for dst.
void FR_Blend_Gamma_Subpixel(FontRenderer *font_renderer, FR_Clip_Area *clip, int x, int y, uint8_t *dst, int dst_width, const FR_Bitmap *glyphs_bitmap, const FR_Bitmap_Glyph_Metrics *glyph, FR_Color color) {
void FR_Blend_Glyph(FontRenderer *font_renderer, FR_Clip_Area *clip, int x, int y, uint8_t *dst, int dst_width, const FR_Bitmap *glyphs_bitmap, const FR_Bitmap_Glyph_Metrics *glyph, FR_Color color) {
agg::gamma_lut<>& gamma = font_renderer->gamma();
agg::lcd_distribution_lut& lcd_lut = font_renderer->lcd_distribution_lut();
const int subpixel_scale = 3;
const int subpixel_scale = font_renderer->subpixel_scale();
const int pixel_size = 4; // Pixel size for BGRA32 format.
x += glyph->xoff;
@ -348,7 +323,11 @@ void FR_Blend_Gamma_Subpixel(FontRenderer *font_renderer, FR_Clip_Area *clip, in
const agg::rgba8 color_a(color.r, color.g, color.b);
for (int x = 0, y = 0; y < glyph_height; y++) {
agg::int8u *covers = src + y * src_stride;
blend_solid_hspan_rgb_subpixel(dst_ren_buf, gamma, lcd_lut, x, y, glyph_width * subpixel_scale, color_a, covers);
if (subpixel_scale == 1) {
blend_solid_hspan<agg::order_bgra>(dst_ren_buf, gamma, x, y, glyph_width, color_a, covers);
} else {
blend_solid_hspan_subpixel<agg::order_bgra>(dst_ren_buf, gamma, lcd_lut, x, y, glyph_width * subpixel_scale, color_a, covers);
}
}
}

28
lib/font_renderer/font_renderer.h
View File

@ -18,9 +18,9 @@ struct FR_Impl;
typedef struct FR_Impl FontRenderer;
enum {
FONT_RENDERER_HINTING = 1 << 0,
FONT_RENDERER_KERNING = 1 << 1,
FONT_RENDERER_SUBPIXEL = 1 << 2,
FR_HINTING = 1 << 0,
FR_KERNING = 1 << 2,
FR_SUBPIXEL = 1 << 3,
};
typedef struct {
@ -32,35 +32,19 @@ typedef struct {
} FR_Clip_Area;
FontRenderer * FR_New(unsigned int flags, float gamma);
void FR_Free(FontRenderer *);
FR_Bitmap* FR_Bitmap_New(FontRenderer *, int width, int height);
int FR_Load_Font(FontRenderer *, const char *filename);
int FR_Get_Font_Height(FontRenderer *, float size);
int FR_Bake_Font_Bitmap(FontRenderer *, int font_height,
FR_Bitmap *image,
int first_char, int num_chars, FR_Bitmap_Glyph_Metrics *glyph_info,
int subpixel_scale);
#if 0
// FIXME: this function needs to be updated to match BlendGammaSubpixel.
void FR_Blend_Gamma(FontRenderer *,
uint8_t *dst, int dst_stride,
uint8_t *src, int src_stride,
int region_width, int region_height,
FR_Color color);
#endif
void FR_Blend_Gamma_Subpixel(FontRenderer *font_renderer,
int first_char, int num_chars, FR_Bitmap_Glyph_Metrics *glyph_info);
void FR_Blend_Glyph(FontRenderer *font_renderer,
FR_Clip_Area *clip, int x, int y,
uint8_t *dst, int dst_width,
const FR_Bitmap *glyphs_bitmap,
const FR_Bitmap_Glyph_Metrics *glyph, FR_Color color);
FR_Bitmap* FR_Bitmap_New(int width, int height, int subpixel_scale);
void FR_Bitmap_Free(FR_Bitmap *image);
#ifdef __cplusplus

11
src/renderer.c
View File

@ -28,7 +28,6 @@ struct RenFont {
static SDL_Window *window;
//static struct { int left, top, right, bottom; } clip;
static FR_Clip_Area clip;
static void* check_alloc(void *ptr) {
@ -107,16 +106,14 @@ void ren_free_image(RenImage *image) {
static GlyphSet* load_glyphset(RenFont *font, int idx) {
GlyphSet *set = check_alloc(calloc(1, sizeof(GlyphSet)));
const int subpixel_scale = 3;
/* init image */
int width = 128;
int height = 128;
retry:
set->image = check_alloc(FR_Bitmap_New(width, height, subpixel_scale));
set->image = check_alloc(FR_Bitmap_New(font->renderer, width, height));
int res = FR_Bake_Font_Bitmap(font->renderer, font->height,
set->image, idx << 8, 256, set->glyphs, subpixel_scale);
set->image, idx << 8, 256, set->glyphs);
/* retry with a larger image buffer if the buffer wasn't large enough */
if (res < 0) {
@ -152,7 +149,7 @@ RenFont* ren_load_font(const char *filename, float size) {
font->size = size;
const float gamma = 1.5;
font->renderer = FR_New(FONT_RENDERER_HINTING|FONT_RENDERER_SUBPIXEL, gamma);
font->renderer = FR_New(FR_HINTING | FR_SUBPIXEL, gamma);
if (FR_Load_Font(font->renderer, filename)) {
free(font);
return NULL;
@ -299,7 +296,7 @@ int ren_draw_text(RenFont *font, const char *text, int x, int y, RenColor color)
GlyphSet *set = get_glyphset(font, codepoint);
FR_Bitmap_Glyph_Metrics *g = &set->glyphs[codepoint & 0xff];
if (color.a != 0) {
FR_Blend_Gamma_Subpixel(font->renderer, &clip,
FR_Blend_Glyph(font->renderer, &clip,
x, y, (uint8_t *) surf->pixels, surf->w, set->image, g, color_fr);
}
x += g->xadvance;