Merge pull request #117 from native-api/png_pred_errors

make ValueError's descriptive
2016-09-11 23:55:34 +09:00 · 2016-09-11 23:55:34 +09:00 · c753dbac4c
parent f1dd9ea6d2 63c9378b8b
commit c753dbac4c
1 changed files with 2 additions and 2 deletions
--- a/pdfminer/utils.py
+++ b/pdfminer/utils.py
@ -11,7 +11,7 @@ from sys import maxint as INF
 def apply_png_predictor(pred, colors, columns, bitspercomponent, data):
    if bitspercomponent != 8:
        # unsupported
-        raise ValueError(bitspercomponent)
+        raise ValueError("Unsupported `bitspercomponent': %d"%bitspercomponent)
    nbytes = colors*columns*bitspercomponent//8
    i = 0
    buf = b''
@ -43,7 +43,7 @@ def apply_png_predictor(pred, colors, columns, bitspercomponent, data):
                line2 += chr(c)
        else:
            # unsupported
-            raise ValueError(ft)
+            raise ValueError("Unsupported predictor value: %d"%ft)
        buf += line2
        line0 = line2
    return buf