Enhanced image convert tool to accept all bit depths as input

Author: Laurence Bank

imageconvert/main.c

@@ -124,13 +124,74 @@ void AddHexBytes(FILE *f, void *pData, int iLen, int bLast)
         fprintf(f, "};\n");
     }
 } /* AddHexBytes() */
+//
+// The user passed a file with the wrong bit depth (not 1)
+// convert to 1-bpp by converting each color to 0 or 1 based on the gray level
+//
+void ConvertTo1Bpp(uint8_t *pBMP, int w, int h, int iBpp, uint8_t *palette)
+{
+    int g, x, y, iDelta, iPitch, iDestPitch;
+    uint8_t *s, *d, *pPal, u8, count;
+    
+    iPitch = (w * iBpp)/8;
+    iPitch = (iPitch + 3) & 0xfffc;
+    iDestPitch = (w+7)/8;
+    iDestPitch = (iDestPitch + 3) & 0xfffc; // round to nearest "DWORD"
+    iDelta = iBpp/8;
+    for (y=0; y<h; y++) {
+        s = &pBMP[iPitch * y];
+        d = &pBMP[iDestPitch * y]; // overwrite the original data as we change it
+        count = 8; // bits in a byte
+        u8 = 0; // start with all black
+        for (x=0; x<w; x++) { // slower code, but less code :)
+            u8 <<= 1;
+            switch (iBpp) {
+                case 24:
+                case 32:
+                    g = (s[0] + s[1]*2 + s[2])/4; // gray value
+                    s += iDelta;
+                    break;
+                case 16:
+                    g = s[1] & 0xf8; // red
+                    g += ((s[0] | s[1] << 8) << 2) & 0x1f0; // green x 2
+                    g += (s[0] << 3) & 0xf8; // blue
+                    g /= 4;
+                    s += 2;
+                    break;
+                case 8:
+                    pPal = &palette[s[0] * 4];
+                    g = (pPal[0] + pPal[1]*2 + pPal[2])/4;
+                    s++;
+                    break;
+                case 4:
+                    if (x & 1) {
+                        pPal = &palette[(s[0] & 0xf) * 4];
+                        g = (pPal[0] + pPal[1]*2 + pPal[2])/4;
+                        s++;
+                    } else {
+                        pPal = &palette[(s[0]>>4) * 4];
+                        g = (pPal[0] + pPal[1]*2 + pPal[2])/4;
+                    }
+                    break;
+            } // switch on bpp
+            if (g >= 128) u8 |= 1; // white
+            count--;
+            if (count == 0) { // byte is full, move on
+                *d++ = u8;
+                u8 = 0;
+                count = 8;
+            }
+        } // for x
+    } // for y
+} /* ConvertTo1Bpp() */
 
 int main(int argc, const char * argv[]) {
-    uint8_t *pBMP, *pOut;
+    uint8_t *s, *pBMP, *pOut;
     int rc, w, h, y, bpp;
     int iOutSize, iPitch;
     G5ENCIMAGE g5enc;
     BB_BITMAP bbbm;
+    uint8_t palette[1024];
     int bHFile; // flag indicating if the output will be a .H file of hex data
 
     printf("Group5 image conversion tool\n");
@@ -141,48 +202,48 @@ int main(int argc, const char * argv[]) {
     pOut = (uint8_t *)argv[2] + strlen(argv[2]) - 1;
     bHFile = (pOut[0] == 'H' || pOut[0] == 'h'); // output an H file?
 
-    pBMP = ReadBMP(argv[1], &w, &h, &bpp, NULL);
-    if (bpp == 1) {
-        uint8_t *s = pBMP;
-        
-        printf("bmp size %d x %d\n", w, h);
-        iPitch = (w+7) >> 3;
-        pOut = (uint8_t *)malloc(iPitch * h);
-        rc = g5_encode_init(&g5enc, w, h, pOut, iPitch * h);
-        for (y=0; y<h && rc == G5_SUCCESS; y++) {
-            rc = g5_encode_encodeLine(&g5enc, s);
-            s += iPitch;
-        }
-        if (rc == G5_ENCODE_COMPLETE) {
-            FILE *f;
-            printf("Encode succeeded!\n");
-            iOutSize = g5_encode_getOutSize(&g5enc);
-            printf("Input size:  %d bytes, output size: %d bytes\n", iPitch*h, iOutSize);
-            printf("Compression ratio: %2.1f:1\n", (float)(iPitch*h) / (float)iOutSize);
-            bbbm.u16Marker = BB_BITMAP_MARKER;
-            bbbm.width = w;
-            bbbm.height = h;
-            bbbm.size = iOutSize;
-            f = fopen(argv[2], "w+b");
-            if (!f) {
-                printf("Error opening: %s\n", argv[2]);
-            } else {
-                if (bHFile) { // generate HEX file to include in a project
-                    StartHexFile(f, iOutSize+sizeof(BB_BITMAP), w, h, argv[2]);
-                    AddHexBytes(f, &bbbm, sizeof(BB_BITMAP), 0);
-                    AddHexBytes(f, pOut, iOutSize, 1);
-                } else { // generate a binary file
-                    fwrite(&bbbm, 1, sizeof(BB_BITMAP), f);
-                    fwrite(pOut, 1, iOutSize, f);
-                }
-                fflush(f);
-                fclose(f);
-            }
+    pBMP = ReadBMP(argv[1], &w, &h, &bpp, palette);
+    if (bpp != 1) { // need to convert it to 1-bpp
+        printf("Converting from %d-bpp to 1-bpp\n", bpp);
+        ConvertTo1Bpp(pBMP, w, h, bpp, palette);
+    }
+    s = pBMP;
+    printf("Bitmap size: %d x %d\n", w, h);
+    iPitch = (w+7) >> 3;
+    pOut = (uint8_t *)malloc(iPitch * h);
+    rc = g5_encode_init(&g5enc, w, h, pOut, iPitch * h);
+    for (y=0; y<h && rc == G5_SUCCESS; y++) {
+        rc = g5_encode_encodeLine(&g5enc, s);
+        s += iPitch;
+    }
+    if (rc == G5_ENCODE_COMPLETE) {
+        FILE *f;
+        iOutSize = g5_encode_getOutSize(&g5enc);
+        printf("Input data size:  %d bytes, compressed size: %d bytes\n", iPitch*h, iOutSize);
+        printf("Compression ratio: %2.1f:1\n", (float)(iPitch*h) / (float)iOutSize);
+        bbbm.u16Marker = BB_BITMAP_MARKER;
+        bbbm.width = w;
+        bbbm.height = h;
+        bbbm.size = iOutSize;
+        f = fopen(argv[2], "w+b");
+        if (!f) {
+            printf("Error opening: %s\n", argv[2]);
         } else {
-            printf("Error encoding image: %d\n", rc);
+            if (bHFile) { // generate HEX file to include in a project
+                StartHexFile(f, iOutSize+sizeof(BB_BITMAP), w, h, argv[2]);
+                AddHexBytes(f, &bbbm, sizeof(BB_BITMAP), 0);
+                AddHexBytes(f, pOut, iOutSize, 1);
+                printf(".H file created successfully!\n");
+            } else { // generate a binary file
+                fwrite(&bbbm, 1, sizeof(BB_BITMAP), f);
+                fwrite(pOut, 1, iOutSize, f);
+                printf("Binary file created successfully!\n");
+            }
+            fflush(f);
+            fclose(f);
         }
     } else {
-        printf("Only 1-bpp images are supported.\n");
+        printf("Error encoding image: %d\n", rc);
     }
     free(pBMP);
     return 0;