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Merge branch 'master' of https://github.com/stefanhaustein/TerminalImageViewer

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stefan.haustein@gmail.com 2017-07-11 21:26:10 +02:00
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README.md
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@ -1,6 +1,6 @@
# TerminalImageViewer
Small Java program to display images in a (modern) terminal using RGB ANSI codes and unicode block graphic characters
Small Java\* program to display images in a (modern) terminal using RGB ANSI codes and unicode block graphic characters.
Algorithm (for each 4x8 pixel cell mapped to a unicode block graphics character):
@ -9,8 +9,9 @@ Algorithm (for each 4x8 pixel cell mapped to a unicode block graphics character)
3. Average the colors above and below and create a corresponding bitmap for the cell
3. Compare the bitmap to the assumed bitmaps for various unicode block graphics characters
\*) **C++ port** available at at https://github.com/stefanhaustein/tiv
Usage:
## Usage
```
javac TerminalImageViewer.java
@ -19,6 +20,13 @@ java TerminalImageViewer [-w <width-in-characters>] <image-filename-or-url>
```
## Common problems
- If you see strange horizontal lines, the characters don't fully fill the character cell. Remove additional line spacing in your terminal app
- Wrong colors? Try -256 to use a 256 color palette instead of 24 bit colors or -grayscale for grayscale.
## Examples
![Examples](http://i.imgur.com/8UyGjg8.png)
If multiple images match the filename spec, thumbnails are shown.

152
src/main/java/TerminalImageViewer.java
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@ -32,7 +32,7 @@ public class TerminalImageViewer {
"Image file name required.\n\n" +
" - Use -w and -h to set the maximum width and height in characters (defaults: 80, 24).\n" +
" - Use -256 for 256 color mode, -grayscale for grayscale and -stdin to obtain file names from stdin.\n" +
" - When multiple files are supplied, -c sets the number of images per row (default: 4).");
" - When multiple files are supplied, -c sets the number of images per row (default: 4).");
return;
}
@ -76,7 +76,7 @@ public class TerminalImageViewer {
} else if (start == args.length - 1 && (isUrl(args[start]) || !new File(args[start]).isDirectory())) {
convert(args[start], maxWidth, maxHeight);
} else {
// Directory-style rendering.
// Directory-style rendering.
int index = 0;
int cw = (maxWidth - 2 * (columns - 1) * 4) / (4 * columns);
int tw = cw * 4;
@ -102,7 +102,7 @@ public class TerminalImageViewer {
sb.setLength(sl - 2);
sb.append(" ");
} catch (Exception e) {
// Probably no image; ignore.
// Probably no image; ignore.
}
}
dump(image, mode);
@ -165,7 +165,7 @@ public class TerminalImageViewer {
/**
* ANSI control code helpers
* ANSI control code helpers
*/
static class Ansi {
public static final String RESET = "\u001b[0m";
@ -182,7 +182,7 @@ public class TerminalImageViewer {
int index = Arrays.binarySearch(options, v);
if (index < 0) {
index = -index - 1;
// need to check [index] and [index - 1]
// need to check [index] and [index - 1]
if (index == options.length) {
index = options.length - 1;
} else if (index > 0) {
@ -232,7 +232,7 @@ public class TerminalImageViewer {
0.3 * sqr(grayQ-r) + 0.59 * sqr(grayQ-g) + 0.11 * sqr(grayQ-b)) {
colorIndex = 16 + 36 * rIdx + 6 * gIdx + bIdx;
} else {
colorIndex = 232 + grayIdx; // 1..24 -> 232..255
colorIndex = 232 + grayIdx; // 1..24 -> 232..255
}
return (bg ? "\u001B[48;5;" : "\u001B[38;5;") + colorIndex + "m";
}
@ -252,94 +252,94 @@ public class TerminalImageViewer {
static int[] BITMAPS = new int[] {
0x00000000, '\u00a0',
// Block graphics
// Block graphics
// 0xffff0000, '\u2580', // upper 1/2; redundant with inverse lower 1/2
// 0xffff0000, '\u2580', // upper 1/2; redundant with inverse lower 1/2
0x0000000f, '\u2581', // lower 1/8
0x000000ff, '\u2582', // lower 1/4
0x0000000f, '\u2581', // lower 1/8
0x000000ff, '\u2582', // lower 1/4
0x00000fff, '\u2583',
0x0000ffff, '\u2584', // lower 1/2
0x0000ffff, '\u2584', // lower 1/2
0x000fffff, '\u2585',
0x00ffffff, '\u2586', // lower 3/4
0x00ffffff, '\u2586', // lower 3/4
0x0fffffff, '\u2587',
// 0xffffffff, '\u2588', // full; redundant with inverse space
// 0xffffffff, '\u2588', // full; redundant with inverse space
0xeeeeeeee, '\u258a', // left 3/4
0xcccccccc, '\u258c', // left 1/2
0x88888888, '\u258e', // left 1/4
0xeeeeeeee, '\u258a', // left 3/4
0xcccccccc, '\u258c', // left 1/2
0x88888888, '\u258e', // left 1/4
0x0000cccc, '\u2596', // quadrant lower left
0x00003333, '\u2597', // quadrant lower right
0xcccc0000, '\u2598', // quadrant upper left
// 0xccccffff, '\u2599', // 3/4 redundant with inverse 1/4
0xcccc3333, '\u259a', // diagonal 1/2
// 0xffffcccc, '\u259b', // 3/4 redundant
// 0xffff3333, '\u259c', // 3/4 redundant
0x33330000, '\u259d', // quadrant upper right
// 0x3333cccc, '\u259e', // 3/4 redundant
// 0x3333ffff, '\u259f', // 3/4 redundant
0x0000cccc, '\u2596', // quadrant lower left
0x00003333, '\u2597', // quadrant lower right
0xcccc0000, '\u2598', // quadrant upper left
// 0xccccffff, '\u2599', // 3/4 redundant with inverse 1/4
0xcccc3333, '\u259a', // diagonal 1/2
// 0xffffcccc, '\u259b', // 3/4 redundant
// 0xffff3333, '\u259c', // 3/4 redundant
0x33330000, '\u259d', // quadrant upper right
// 0x3333cccc, '\u259e', // 3/4 redundant
// 0x3333ffff, '\u259f', // 3/4 redundant
// Line drawing subset: no double lines, no complex light lines
// Simple light lines duplicated because there is no center pixel int the 4x8 matrix
// Line drawing subset: no double lines, no complex light lines
// Simple light lines duplicated because there is no center pixel int the 4x8 matrix
0x000ff000, '\u2501', // Heavy horizontal
0x66666666, '\u2503', // Heavy vertical
0x000ff000, '\u2501', // Heavy horizontal
0x66666666, '\u2503', // Heavy vertical
0x00077666, '\u250f', // Heavy down and right
0x000ee666, '\u2513', // Heavy down and left
0x66677000, '\u2517', // Heavy up and right
0x666ee000, '\u251b', // Heavy up and left
0x00077666, '\u250f', // Heavy down and right
0x000ee666, '\u2513', // Heavy down and left
0x66677000, '\u2517', // Heavy up and right
0x666ee000, '\u251b', // Heavy up and left
0x66677666, '\u2523', // Heavy vertical and right
0x666ee666, '\u252b', // Heavy vertical and left
0x000ff666, '\u2533', // Heavy down and horizontal
0x666ff000, '\u253b', // Heavy up and horizontal
0x666ff666, '\u254b', // Heavy cross
0x66677666, '\u2523', // Heavy vertical and right
0x666ee666, '\u252b', // Heavy vertical and left
0x000ff666, '\u2533', // Heavy down and horizontal
0x666ff000, '\u253b', // Heavy up and horizontal
0x666ff666, '\u254b', // Heavy cross
0x000cc000, '\u2578', // Bold horizontal left
0x00066000, '\u2579', // Bold horizontal up
0x00033000, '\u257a', // Bold horizontal right
0x00066000, '\u257b', // Bold horizontal down
0x000cc000, '\u2578', // Bold horizontal left
0x00066000, '\u2579', // Bold horizontal up
0x00033000, '\u257a', // Bold horizontal right
0x00066000, '\u257b', // Bold horizontal down
0x06600660, '\u254f', // Heavy double dash vertical
0x06600660, '\u254f', // Heavy double dash vertical
0x000f0000, '\u2500', // Light horizontal
0x0000f000, '\u2500', //
0x44444444, '\u2502', // Light vertical
0x44444444, '\u2502', // Light vertical
0x22222222, '\u2502',
0x000e0000, '\u2574', // light left
0x0000e000, '\u2574', // light left
0x44440000, '\u2575', // light up
0x22220000, '\u2575', // light up
0x00030000, '\u2576', // light right
0x00003000, '\u2576', // light right
0x00004444, '\u2575', // light down
0x00002222, '\u2575', // light down
0x000e0000, '\u2574', // light left
0x0000e000, '\u2574', // light left
0x44440000, '\u2575', // light up
0x22220000, '\u2575', // light up
0x00030000, '\u2576', // light right
0x00003000, '\u2576', // light right
0x00004444, '\u2575', // light down
0x00002222, '\u2575', // light down
// Misc technical
// Misc technical
0x44444444, '\u23a2', // [ extension
0x22222222, '\u23a5', // ] extension
0x44444444, '\u23a2', // [ extension
0x22222222, '\u23a5', // ] extension
//12345678
0x0f000000, '\u23ba', // Horizontal scanline 1
0x00f00000, '\u23bb', // Horizontal scanline 3
0x00000f00, '\u23bc', // Horizontal scanline 7
0x000000f0, '\u23bd', // Horizontal scanline 9
0x0f000000, '\u23ba', // Horizontal scanline 1
0x00f00000, '\u23bb', // Horizontal scanline 3
0x00000f00, '\u23bc', // Horizontal scanline 7
0x000000f0, '\u23bd', // Horizontal scanline 9
// Geometrical shapes. Tricky because some of them are too wide.
// Geometrical shapes. Tricky because some of them are too wide.
// 0x00ffff00, '\u25fe', // Black medium small square
0x00066000, '\u25aa', // Black small square
// 0x00ffff00, '\u25fe', // Black medium small square
0x00066000, '\u25aa', // Black small square
/*
0x11224488, '\u2571', // diagonals
0x11224488, '\u2571', // diagonals
0x88442211, '\u2572',
0x99666699, '\u2573',
0x000137f0, '\u25e2', // Triangles
0x000137f0, '\u25e2', // Triangles
0x0008cef0, '\u25e3',
0x000fec80, '\u25e4',
0x000f7310, '\u25e5'
@ -372,7 +372,7 @@ public class TerminalImageViewer {
Arrays.fill(bgColor, 0);
Arrays.fill(fgColor, 0);
// Determine the minimum and maximum value for each color channel
// Determine the minimum and maximum value for each color channel
int pos = p0;
for (int y = 0; y < 8; y++) {
for (int x = 0; x < 4; x++) {
@ -381,12 +381,12 @@ public class TerminalImageViewer {
min[i] = Math.min(min[i], d);
max[i] = Math.max(max[i], d);
}
pos++; // Alpha
pos++; // Alpha
}
pos += scanWidth - 16;
}
// Determine the color channel with the greatest range.
// Determine the color channel with the greatest range.
int splitIndex = 0;
int bestSplit = 0;
for (int i = 0; i < 3; i++) {
@ -395,10 +395,10 @@ public class TerminalImageViewer {
splitIndex = i;
}
}
// We just split at the middle of the interval instead of computing the median.
// We just split at the middle of the interval instead of computing the median.
int splitValue = min[splitIndex] + bestSplit / 2;
// Compute a bitmap using the given split and sum the color values for both buckets.
// Compute a bitmap using the given split and sum the color values for both buckets.
int bits = 0;
int fgCount = 0;
int bgCount = 0;
@ -419,12 +419,12 @@ public class TerminalImageViewer {
for (int i = 0; i < 3; i++) {
avg[i] += data[pos++] & 255;
}
pos++; // Alpha
pos++; // Alpha
}
pos += scanWidth - 16;
}
// Calculate the average color value for each bucket
// Calculate the average color value for each bucket
for (int i = 0; i < 3; i++) {
if (bgCount != 0) {
bgColor[i] /= bgCount;
@ -434,8 +434,8 @@ public class TerminalImageViewer {
}
}
// Find the best bitmap match by counting the bits that don't match, including
// the inverted bitmaps.
// Find the best bitmap match by counting the bits that don't match, including
// the inverted bitmaps.
int bestDiff = Integer.MAX_VALUE;
boolean invert = false;
for (int i = 0; i < BITMAPS.length; i += 2) {
@ -453,13 +453,13 @@ public class TerminalImageViewer {
}
}
// If the match is quite bad, use a shade image instead.
// If the match is quite bad, use a shade image instead.
if (bestDiff > 10) {
invert = false;
character = " \u2591\u2592\u2593\u2588".charAt(Math.min(4, fgCount * 5 / 32));
}
// If we use an inverted character, we need to swap the colors.
// If we use an inverted character, we need to swap the colors.
if (invert) {
int[] tmp = bgColor;
bgColor = fgColor;