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lvdrawbuf: handle text and background colors with alpha
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In Draw(glyph bitmap) and FillRect(), so for text and
background colors (only implemented for bpp=8/16/32).
Enable alpha values when parsing CSS colors.
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@poire-z
poire-z committed Apr 6, 2022
1 parent c7b6737 commit ada7342
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Showing 3 changed files with 66 additions and 37 deletions.
92 changes: 62 additions & 30 deletions crengine/src/lvdrawbuf.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -905,6 +905,9 @@ void LVGrayDrawBuf::FillRect( int x0, int y0, int x1, int y1, lUInt32 color32 )
if (x0>=x1 || y0>=y1)
return;
lUInt8 color = rgbToGrayMask( color32, _bpp );
const lUInt8 opacity = ~color32 >> 24;
if (opacity == 0) // Fully transparent color
return;
#if (GRAY_INVERSE==1)
color ^= 0xFF;
#endif
Expand All @@ -926,8 +929,15 @@ void LVGrayDrawBuf::FillRect( int x0, int y0, int x1, int y1, lUInt32 color32 )
line[index] = (lUInt8)((line[index] & ~mask) | (color & mask));
}
} else { // 3, 4, 8
for (int x=x0; x<x1; x++)
line[x] = color;
if ( opacity == 0xFF ) {
for (int x=x0; x<x1; x++)
line[x] = color;
}
else {
const lUInt8 alpha = opacity ^ 0xFF;
for (int x=x0; x<x1; x++)
ApplyAlphaGray8( line[x], color, alpha, opacity );
}
}
line += _rowsize;
}
Expand Down Expand Up @@ -1249,24 +1259,31 @@ void LVGrayDrawBuf::Draw( int x, int y, const lUInt8 * bitmap, int width, int he
// true : false;
//#endif

// Note: support for TextColor opacity/alpha was added only in the _bpp==8 branch
if ( _bpp==8 ) {
lUInt8 * dstline = _data + _rowsize*y + x;
const lUInt8 color = rgbToGrayMask(GetTextColor(), 8);
const lUInt8 bopacity = ~GetTextColor() >> 24;
if (bopacity == 0) // Fully transparent color
return;
while (height--)
{
const lUInt8 * __restrict src = bitmap;
lUInt8 * __restrict dst = dstline;
size_t px_count = width;
while (px_count--)
{
const lUInt8 opaque = (*src++);
if ( opaque == 0 ) {
lUInt8 opacity = *(src++); // glyph opacity
if ( opacity == 0 ) {
// Background pixel, NOP
} else if ( opaque == 0xFF ) {
}
else if (opacity == 0xFF && bopacity == 0xFF) { // fully opaque pixel and color
*dst = color;
} else {
const lUInt8 alpha = opaque ^ 0xFF;
ApplyAlphaGray8( *dst, color, alpha, opaque );
}
else {
opacity = (opacity*bopacity)>>8;
const lUInt8 alpha = opacity ^ 0xFF;
ApplyAlphaGray8( *dst, color, alpha, opacity );
}
dst++;
}
Expand Down Expand Up @@ -1660,6 +1677,8 @@ void LVColorDrawBuf::FillRect( int x0, int y0, int x1, int y1, lUInt32 color )
if (x0>=x1 || y0>=y1)
return;
const lUInt8 alpha = (color >> 24) & 0xFF;
if (alpha == 0xFF) // Fully transparent color
return;
if ( _bpp==16 ) {
const lUInt16 cl16 = rgb888to565(color);
for (int y=y0; y<y1; y++)
Expand Down Expand Up @@ -1910,6 +1929,9 @@ void LVColorDrawBuf::Draw( int x, int y, const lUInt8 * bitmap, int width, int h

if ( _bpp==16 ) {
const lUInt16 bmpcl16 = rgb888to565(bmpcl);
const lUInt8 bopacity = ~bmpcl >> 24; // alpha=0x00 => opacity=0xFF
if (bopacity == 0) // Fully transparent color
return;

while (height--)
{
Expand All @@ -1919,24 +1941,33 @@ void LVColorDrawBuf::Draw( int x, int y, const lUInt8 * bitmap, int width, int h
size_t px_count = width;
while (px_count--)
{
const lUInt8 opaque = ((*(src++))>>4)&0x0F;
if ( opaque==0 ) {
// Note: former code was considering pixel opacity >= 0xF0 as fully opaque (0xFF),
// not sure why (it would save on the blending computation by 5% to 15%).
lUInt8 opacity = *(src++); // glyph pixel opacity
if ( opacity == 0 ) {
// Background pixel, NOP
} else if ( opaque>=0xF ) {
}
else if (opacity == 0xFF && bopacity == 0xFF) { // fully opaque pixel and color
*dst = bmpcl16;
} else {
const lUInt8 alpha = 0xF-opaque;
const lUInt16 cl1 = (lUInt16)(((alpha*((*dst)&0xF81F) + opaque*(bmpcl16&0xF81F))>>4) & 0xF81F);
const lUInt16 cl2 = (lUInt16)(((alpha*((*dst)&0x07E0) + opaque*(bmpcl16&0x07E0))>>4) & 0x07E0);
*dst = cl1 | cl2;
}
else {
opacity = (opacity*bopacity)>>8;
const lUInt8 alpha = opacity ^ 0xFF;
const lUInt32 r = ((((*dst) & 0xF800) * alpha + (bmpcl16 & 0xF800) * opacity) >> 8) & 0xF800;
const lUInt32 g = ((((*dst) & 0x07E0) * alpha + (bmpcl16 & 0x07E0) * opacity) >> 8) & 0x07E0;
const lUInt32 b = ((((*dst) & 0x001F) * alpha + (bmpcl16 & 0x001F) * opacity) >> 8) & 0x001F;
*dst = (lUInt16)(r | g | b);
}
dst++;
}
/* new src line, to account for clipping */
bitmap += bmp_width;
}
} else {
const lUInt32 bmpcl32 = bmpcl;
const lUInt32 bmpcl32 = bmpcl & 0x00FFFFFF;
const lUInt8 bopacity = ~bmpcl >> 24; // alpha=0x00 => opacity=0xFF
if (bopacity == 0) // Fully transparent color
return;

while (height--)
{
Expand All @@ -1946,24 +1977,25 @@ void LVColorDrawBuf::Draw( int x, int y, const lUInt8 * bitmap, int width, int h
size_t px_count = width;
while (px_count--)
{
// NOTE: Not quite sure what's the rationale for the funky semi half-precision alpha-blending there...
const lUInt8 opaque = ((*(src++))>>1)&0x7F;
if ( opaque==0 ) {
// Note: former code was considering pixel opacity >= 0xF0 as fully opaque (0xFF),
// not sure why (it would save on the blending computation by 5% to 15%).
lUInt8 opacity = *(src++); // glyph pixel opacity
if ( opacity == 0 ) {
// Background pixel, NOP
} else if ( opaque>=0x78 ) {
}
else if (opacity == 0xFF && bopacity == 0xFF) { // fully opaque pixel and color
*dst = bmpcl32;
} else {
const lUInt8 alpha = 0x7F-opaque;
const lUInt32 cl1 = ((alpha*((*dst)&0xFF00FF) + opaque*(bmpcl32&0xFF00FF))>>7) & 0xFF00FF;
const lUInt32 cl2 = ((alpha*((*dst)&0x00FF00) + opaque*(bmpcl32&0x00FF00))>>7) & 0x00FF00;
// NOTE: We're skipping the alpha byte here, because CRe uses inverted alpha :(
// Which means that the masking shenanigans above ensure it's 0x00, fully opaque...
// (c.f., ApplyAlphaRGB, which does the same thing without the weird half-precision hack).
*dst = cl1 | cl2;
}
else {
opacity = (opacity*bopacity)>>8;
const lUInt8 alpha = opacity ^ 0xFF;
const lUInt32 n1 = ((((*dst) & 0xFF00FF) * alpha + (bmpcl32 & 0xFF00FF) * opacity) >> 8) & 0xFF00FF;
const lUInt32 n2 = ((((*dst) & 0x00FF00) * alpha + (bmpcl32 & 0x00FF00) * opacity) >> 8) & 0x00FF00;
*dst = n1 | n2;
}

dst++;
}
/* next src line, accounting for clipping */
bitmap += bmp_width;
}
}
Expand Down
9 changes: 3 additions & 6 deletions crengine/src/lvstsheet.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1167,8 +1167,7 @@ bool parse_color_value( const char * & str, css_length_t & value )
if ( nDigits==4 ) {
int a = hexDigit( *str++ );
// cre color upper byte is inverted alpha (0x00=opaque, 0xFF=transparency)
// value.value |= ((a + a*16)^0xFF)<<24;
// Disabled for now, as support for alpha needs work
value.value |= ((a + a*16)^0xFF)<<24;
}
return true;
} else if ( nDigits==6 || nDigits==8 ) {
Expand All @@ -1184,8 +1183,7 @@ bool parse_color_value( const char * & str, css_length_t & value )
int a = hexDigit( *str++ ) * 16;
a += hexDigit( *str++ );
// cre color upper byte is inverted alpha
// value.value |= ((a + a*16)^0xFF)<<24;
// Disabled for now, as support for alpha needs work
value.value |= ((a + a*16)^0xFF)<<24;
}
return true;
} else {
Expand Down Expand Up @@ -1297,8 +1295,7 @@ bool parse_color_value( const char * & str, css_length_t & value )
break;
}
// cre color upper byte is inverted alpha (0x00=opaque, 0xFF=transparency)
// color = ((n^0xFF)<<24) | color;
// Disabled for now, as support for alpha needs work
color = ((n^0xFF)<<24) | color;
}
else {
valid = false;
Expand Down
2 changes: 1 addition & 1 deletion crengine/src/lvtinydom.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -90,7 +90,7 @@ extern const int gDOMVersionCurrent = DOM_VERSION_CURRENT;
// increment to force complete reload/reparsing of old file
#define CACHE_FILE_FORMAT_VERSION "3.05.67k"
/// increment following value to force re-formatting of old book after load
#define FORMATTING_VERSION_ID 0x002B
#define FORMATTING_VERSION_ID 0x002C

#ifndef DOC_DATA_COMPRESSION_LEVEL
/// data compression level (0=no compression, 1=fast compressions, 3=normal compression)
Expand Down

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