You can use the set_paper
method (in versions 0.6 or earlier) or the setPaper
method (in versions 0.7 or higher) stating the size you want.
In class Dompdf\Adapter\CPDF
you have all the options. I'm putting them right below:
static $PAPER_SIZES = array(
"4a0" => array(0, 0, 4767.87, 6740.79),
"2a0" => array(0, 0, 3370.39, 4767.87),
"a0" => array(0, 0, 2383.94, 3370.39),
"a1" => array(0, 0, 1683.78, 2383.94),
"a2" => array(0, 0, 1190.55, 1683.78),
"a3" => array(0, 0, 841.89, 1190.55),
"a4" => array(0, 0, 595.28, 841.89),
"a5" => array(0, 0, 419.53, 595.28),
"a6" => array(0, 0, 297.64, 419.53),
"a7" => array(0, 0, 209.76, 297.64),
"a8" => array(0, 0, 147.40, 209.76),
"a9" => array(0, 0, 104.88, 147.40),
"a10" => array(0, 0, 73.70, 104.88),
"b0" => array(0, 0, 2834.65, 4008.19),
"b1" => array(0, 0, 2004.09, 2834.65),
"b2" => array(0, 0, 1417.32, 2004.09),
"b3" => array(0, 0, 1000.63, 1417.32),
"b4" => array(0, 0, 708.66, 1000.63),
"b5" => array(0, 0, 498.90, 708.66),
"b6" => array(0, 0, 354.33, 498.90),
"b7" => array(0, 0, 249.45, 354.33),
"b8" => array(0, 0, 175.75, 249.45),
"b9" => array(0, 0, 124.72, 175.75),
"b10" => array(0, 0, 87.87, 124.72),
"c0" => array(0, 0, 2599.37, 3676.54),
"c1" => array(0, 0, 1836.85, 2599.37),
"c2" => array(0, 0, 1298.27, 1836.85),
"c3" => array(0, 0, 918.43, 1298.27),
"c4" => array(0, 0, 649.13, 918.43),
"c5" => array(0, 0, 459.21, 649.13),
"c6" => array(0, 0, 323.15, 459.21),
"c7" => array(0, 0, 229.61, 323.15),
"c8" => array(0, 0, 161.57, 229.61),
"c9" => array(0, 0, 113.39, 161.57),
"c10" => array(0, 0, 79.37, 113.39),
"ra0" => array(0, 0, 2437.80, 3458.27),
"ra1" => array(0, 0, 1729.13, 2437.80),
"ra2" => array(0, 0, 1218.90, 1729.13),
"ra3" => array(0, 0, 864.57, 1218.90),
"ra4" => array(0, 0, 609.45, 864.57),
"sra0" => array(0, 0, 2551.18, 3628.35),
"sra1" => array(0, 0, 1814.17, 2551.18),
"sra2" => array(0, 0, 1275.59, 1814.17),
"sra3" => array(0, 0, 907.09, 1275.59),
"sra4" => array(0, 0, 637.80, 907.09),
"letter" => array(0, 0, 612.00, 792.00),
"legal" => array(0, 0, 612.00, 1008.00),
"ledger" => array(0, 0, 1224.00, 792.00),
"tabloid" => array(0, 0, 792.00, 1224.00),
"executive" => array(0, 0, 521.86, 756.00),
"folio" => array(0, 0, 612.00, 936.00),
"commercial #10 envelope" => array(0, 0, 684, 297),
"catalog #10 1/2 envelope" => array(0, 0, 648, 864),
"8.5x11" => array(0, 0, 612.00, 792.00),
"8.5x14" => array(0, 0, 612.00, 1008.0),
"11x17" => array(0, 0, 792.00, 1224.00),
);
In this case it's in pixels, so I can not tell which option to select, but I'm sure some of those should help.