How to extract image from a bitmapped font

Storyyeller · 2011-09-09T13:20:28+00:00

So I need a small bitmapped font for a retro game I am working on. I found several sites offering free bitmapped fonts for download which look suitable. However, they are always in the ttf format, and I can't figure out any way to extract the actual image data. What should I do?

I expect you can use SDL to render the font glyphs onto a surface and save that, but since I haven't used fonts with SDL I can't help with that.

GDI is pretty easy. In fact I have some code here which renders all the ASCII characters for any given font. Hope it helps.


 /// create font
 ///param font Win32 font handle
 ///param sz wSize of font
 ///param fg foreground colour
 ///param bg background colour
 ///param hdc Win32 device context handle
 ///return rectangle representing bounds of drawn area
 RECT texmapfont::Create(HFONT font, WORD sz, COLORREF fg, COLORREF bg, HDC hdc) {
 // allocate and clear pBitmap data
 SetSize(sz);
 // create windows hdc and pBitmap
 HBITMAP hbm = 0;
 HGDIOBJ oldgdiobj[2];
 if (hdc == 0) {
 HDC tdc = GetDC(NULL);
 hdc = CreateCompatibleDC(tdc);
 hbm = CreateCompatibleBitmap(tdc, wSize, wSize);
 oldgdiobj[0] = SelectObject(hdc, hbm);
 ReleaseDC(NULL, tdc);
 }
 // create and fill character buffer with ASCII characters 32-126
 char buffer[256-32];
 for (int i = 0; i < 255-32; i++)
 buffer = 32 + i;
 buffer[255-32] = 0;
 // set text colours
 SetTextColor(hdc, RGB(255,255,255));
 SetBkColor(hdc, RGB(0, 0, 0));
 // wipe DC to black
 HBRUSH hb = CreateSolidBrush(RGB(255,0,0));
 RECT rc = {0, 0, wSize, wSize};
 FillRect(hdc, &rc, hb);
 DeleteObject(hb);
 // set font details
 oldgdiobj[1] = SelectObject(hdc, font);
 LOGFONT lf;
 GetObject(font, sizeof(LOGFONT), &lf);
 name = lf.lfFaceName;
 dwItalic = lf.lfItalic;
 dwWeight = lf.lfWeight;
 // draw glyphs
 GLYPHMETRICS gm;
 MAT2 matrix;
 char txt[2] = {0, 0};
 memset(&gm, 0, sizeof(gm));
 memset(&matrix, 0, sizeof(matrix));
 matrix.eM11.value = 1;
 matrix.eM22.value = 1;
 int sx = 0, sy = 0; // glyph rcPos
 for (int i = 0; i < 255-32; i++) {
 // calculate glyph wSize
 int wOhl = 0, wOhr = 0; // overhang left/right
 txt[0] = buffer;
 rc.left = sx; rc.top = sy;
 rc.right = rc.bottom = wSize - 1;
 DrawText(hdc, txt, 1, &rc, DT_LEFT|DT_CALCRECT|DT_NOPREFIX);
 GetGlyphOutline(hdc, buffer, GGO_METRICS, &gm, 0, NULL, &matrix);
 if (gm.gmptGlyphOrigin.x < 0) {
 // glyph overhangs left edge
 wOhl = gm.gmptGlyphOrigin.x;
 rc.left -= gm.gmptGlyphOrigin.x;
 rc.right = rc.left + gm.gmCellIncX;
 }
 if (gm.gmptGlyphOrigin.x + gm.gmBlackBoxX > (WORD)(rc.right - rc.left)) {
 // glyph overhangs right edge
 wOhr = (gm.gmptGlyphOrigin.x + gm.gmBlackBoxX) - (rc.right - rc.left);
 rc.right = rc.left + gm.gmptGlyphOrigin.x + gm.gmBlackBoxX;
 }
 // rercPos if over end of line
 if ((DWORD)rc.right >= wSize) {
 sx = 0;
 sy += rc.bottom - rc.top;
 if ((DWORD)sx >= wSize)
 break;
 rc.left = sx; rc.top = sy;
 rc.right = rc.bottom = wSize - 1;
 DrawText(hdc, txt, 1, &rc, DT_LEFT|DT_CALCRECT|DT_NOPREFIX);
 if (gm.gmptGlyphOrigin.x < 0) {
 // glyph overhangs left edge
 wOhl = gm.gmptGlyphOrigin.x;
 rc.left -= gm.gmptGlyphOrigin.x;
 rc.right = rc.left + gm.gmCellIncX;
 }
 if (gm.gmptGlyphOrigin.x + gm.gmBlackBoxX > (WORD)(rc.right - rc.left)) {
 // glyph overhangs right edge
 wOhr = (gm.gmptGlyphOrigin.x + gm.gmBlackBoxX) - (rc.right - rc.left);
 rc.right = rc.left + gm.gmptGlyphOrigin.x + gm.gmBlackBoxX;
 }
 }
 // draw glyph
 DrawText(hdc, txt, 1, &rc, DT_LEFT|DT_NOPREFIX|DT_NOCLIP);
 // store glyph info in array
 glyph.bValue = txt[0];
 glyph.wOhl = -wOhl;
 glyph.wOhr = wOhr;
 glyph.rcPos.left = (WORD)rc.left + wOhl;
 glyph.rcPos.top = (WORD)rc.top;
 glyph.rcPos.right = (WORD)rc.right;
 glyph.rcPos.bottom = (WORD)rc.bottom;
 // move draw rcPos
 sx = rc.right;
 }
 SelectObject(hdc, oldgdiobj[1]);
 // copy drawn data to pBitmap data
 COLORREF pv;
 for (DWORD iy = 0; iy < wSize; iy++) {
 for (DWORD ix = 0; ix < wSize; ix++) {
 pv = GetPixel(hdc, ix, iy);
 pBitmap[iy * wSize + ix] = (BYTE)(pv & 0xFF);
 }
 }
 if (hbm != 0) {
 SelectObject(hdc, oldgdiobj[0]);
 DeleteObject(hbm);
 DeleteDC(hdc);
 }
 dwHeight = glyph[0].rcPos.bottom;
 rc.left = rc.top = 0;
 RECT ret = { (WORD)rc.left, (WORD)rc.top, (WORD)rc.right, (WORD)rc.bottom };
 return ret;
 }

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