全网首发：OSD字幕时，字体数据、间距的正确处理

比如说：如果是巍宇，这字好处理；如果是一丨，字体数据只有一行，数据如何刷新处理？间距又如何处理？

别担心。我这里有现成的代码。

• 先看处理结果

https://blog.csdn.net/quantum7/article/details/153679213

• FreeType字体加载

这个各位想必很熟悉了。

FT_Library m_pFTLib = NULL; FT_Face m_pFTFace = NULL; int m_iFontSize = 16; FT_Init_FreeType(&m_pFTLib); if (FT_New_Face(m_pFTLib, mFontFile, 0, &m_pFTFace)) { WY_LOG_TEXT("FT_New_Face error!"); return; } //FT_ENCODING_GB2312, FT_ENCODING_UNICODE FT_Select_Charmap(m_pFTFace, FT_ENCODING_UNICODE); FT_Set_Char_Size (m_pFTFace, 0, m_iFontSize<<6, 200, 200);

• 加载字符插槽

使用的是Slot而不是Glyph。

因为代码是用于字幕，字幕字符是固定的，所以使用了一个std::map保存起来。

static FT_GlyphSlot osd_load_char_glyph(const wchar_t wch, const FT_Face& pFTFace) { FT_GlyphSlot wslot = new FT_GlyphSlotRec(); int result = FT_Load_Char( pFTFace, wch, FT_LOAD_RENDER ); FT_GlyphSlot slot = pFTFace->glyph; memcpy(wslot, slot, sizeof(FT_GlyphSlotRec)); FT_Bitmap* bmp = &(slot->bitmap); int size = bmp->rows*bmp->width; wslot->bitmap.buffer = (unsigned char*)malloc(size); memcpy(wslot->bitmap.buffer, bmp->buffer, size); return wglyph; }

• 正确处理数据及间距

#define COLOR_TO_PIXEL(pixel, color, v, index) {int temp = color.val[index]*v/0xFF; \ if (temp == 0 && color.val[index] != 0) temp = 1; \ pixel[index] = temp; } #define COLOR_R_INDEX 2 #define COLOR_G_INDEX 1 #define COLOR_B_INDEX 0 void refresh(cv::Mat& rgb, cv::Scalar& color, int startX, int startY) { bool isBlack = (color.val[0] == 0 && color.val[1] == 0 && color.val[2] == 0); for (int i=0; i<this->mTextCount; i++) { wchar_t wch = this->mText[i]; std::map<wchar_t, FT_GlyphSlot>::iterator it = mTextGlyphMap.find(wch); FT_GlyphSlot pSlot = it->second; FT_Bitmap* pBmp = &(pSlot->bitmap); int osdW=pBmp->width; int osdH=pBmp->rows; int osdX = startX+pSlot->bitmap_left; //高度是pSlot->metrics.vertAdvance/64，因为要绘制，所以要减去 int osdY = startY+(pSlot->metrics.vertAdvance/64-pSlot->bitmap_top); for (int j=0; j<osdH; j++){ for (int i=0; i<osdW; i++){ unsigned char v = pBmp->buffer[osdW*j+i]; if (v < MIN_FONT_VALUE) { continue; } cv::Vec3b& pixel = rgb.at<cv::Vec3b>(osdY+j, osdX+i); if (isBlack) { v = 0xFF-v; pixel[COLOR_B_INDEX] = v; pixel[COLOR_G_INDEX] = v; pixel[COLOR_R_INDEX] = v; } else { COLOR_TO_PIXEL(pixel, color, v, COLOR_B_INDEX); COLOR_TO_PIXEL(pixel, color, v, COLOR_G_INDEX); COLOR_TO_PIXEL(pixel, color, v, COLOR_R_INDEX); } } } // 这个是正确宽度 startX += pSlot->metrics.horiAdvance/64; } }